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The Economics of Custom Software Just Changed

September 16, 202620 min read
The Economics of Custom Software Just Changed

There has never been a better time to build with technology. But how you build matters more than ever.

Every company has problems it has learned to live with.

A manual process that consumes thousands of employee hours every year. An aging application that’s expensive and risky to maintain but has never quite justified the investment to replace. A workflow held together by spreadsheets, disconnected systems, and people who know how to “make it work.” Or a growth opportunity that could improve margins, throughput, or the customer experience - but would have taken too long and cost too much to pursue.

For years, the answer to these problems was often perfectly rational:

It’s frustrating. But custom software isn’t worth the investment.

AI is changing that answer.

We’re entering a period where the productive capacity of software teams is changing dramatically. Ideas can be validated faster. Experienced engineers can accomplish more. Modernization can happen differently. And opportunities that couldn’t justify custom technology a few years ago may deserve another look today.

That makes this an extraordinarily exciting time to build - and an important time to reconsider what your business isn’t building.

Because these economics aren’t changing for your company alone.

Your competitors have access to the same capabilities. They’re looking at the same opportunities to automate expensive work, modernize aging systems, improve customer experiences, increase capacity, and bring new ideas to market faster.

The opportunity isn’t to chase AI because everyone else is.

It’s to recognize where AI has changed the economics of a meaningful business problem before that opportunity becomes obvious to everyone.

At one extreme, you’ll hear that AI is overhyped and won’t meaningfully change how businesses build software. At the other, you’ll hear that AI can build virtually anything and experienced developers are becoming unnecessary.

Neither extreme is particularly useful.

The evidence increasingly points to a much more interesting reality: AI is materially increasing what experienced software teams can accomplish, but code is only one part of getting from a business problem to a production solution that creates measurable value.

AI creates speed. The advantage comes from knowing where to point it.


AI Isn’t Just Changing How We Build. It’s Changing What Is Worth Building.

The evidence that AI is changing software development has become considerably stronger.

In 2026, Management Science published research combining three randomized field experiments involving 4,867 professional software developers at Microsoft, Accenture, and an anonymous Fortune 100 company.

These weren’t developers completing an artificial coding exercise. The experiments took place within normal enterprise development environments.

Developers given access to AI coding assistance completed approximately 26% more development tasks than those without it.¹

That’s significant.

But an even larger 2026 study reveals something more important about where the opportunity - and the challenge - really sits.

Researchers analyzed AI adoption across more than 500,000 GitHub developers as development tools progressed from autocomplete to interactive coding agents and autonomous coding agents.

With autonomous agents, the researchers found approximately:

240% increase in coding activity

80% increase in projects

30% increase in actual software releases²

Think about that gap.

AI can dramatically increase the amount of code being produced.

But getting that code all the way into finished, released software is another matter.

Architecture still matters. Business requirements still matter. Security, testing, integrations, infrastructure, deployment, compliance, reliability, product ownership, and user validation still matter.

As coding gets faster, those other parts of the system become increasingly important.

That’s why Gartner’s 2026 research says AI is reshaping software engineering while increasing - not eliminating - the demand for software engineers. Gartner expects AI to allow smaller teams to focus more of their time on complex problem-solving and innovation, while demand for sophisticated software and AI-enabled applications continues to grow.³

This leads to a much more useful conclusion than either “AI changes everything” or “AI is overhyped.”

AI is making code less scarce. That makes judgment more valuable, not less.


And That’s Why the Economics Are Changing

If experienced teams can explore, develop, test, document, and improve software more efficiently, the threshold at which custom software makes economic sense begins to move.

That means business leaders should be revisiting assumptions made even a few years ago.

What did we decide wasn’t worth automating?

What application did we decide was too expensive to modernize?

What growth constraint have we been solving by adding people?

What opportunity did we put on the shelf because building the technology would take too long?

Software that couldn’t justify the investment three years ago may make tremendous business sense today.

The economics behind those decisions are changing.

The decisions may need to change with them.

And there’s a cost to leaving those assumptions unexamined.

Every year an expensive manual process remains manual, the business continues absorbing that cost. Every quarter a legacy system constrains change, the organization continues carrying its risk. Every month a scalable opportunity sits on the roadmap, a competitor has the opportunity to solve the same problem first.

That doesn’t mean every old idea suddenly deserves investment.

It means yesterday’s “no” shouldn’t automatically become today’s “no.”

Some of the highest-value technology opportunities inside your company may already be familiar problems that simply need to be evaluated against today’s economics.


What Used to Take Months - or Years - Is Being Reconsidered

This isn’t theoretical. Across industries, companies are already demonstrating what can happen when experienced teams combine AI with disciplined software engineering.

From 3–12+ Months to Two Weeks

A healthcare software company had modernization initiatives that traditional estimates placed anywhere from three months to more than a year.

Using agentic AI alongside experienced engineering teams, five application modernization projects were reportedly completed in two weeks.

Think about what changes when a timeline like that moves.

Modernization stops being purely a technical conversation. Applications the business has tolerated because replacement couldn’t justify the disruption may suddenly deserve a new economic analysis.

From Nine Months to Days

T-Mobile had an internal application that was estimated to require more than nine months of traditional custom development.

Using a different AI-enabled development approach, the core solution was reportedly created in less than a week.

That doesn’t mean every nine-month project can suddenly be completed in days.

It demonstrates something more important:

The assumptions we use to estimate what’s economically feasible are changing.

350,000 Lines of Legacy Software. Four Months.

Altisource faced another familiar challenge: legacy software.

The company reportedly modernized approximately 350,000 lines of legacy code and delivered four new applications in four months, with an explicit objective of generating greater business value without increasing expense.

For organizations carrying years of technical debt, that’s an important idea.

The business case for modernization doesn’t only change when the old system becomes more expensive.

It can also change when modernization itself becomes more economical.


Look for the Business Problems Hiding in Plain Sight

The best opportunities for AI-fueled custom software probably aren’t sitting on a list labeled “AI Projects.”

They’re already embedded in the business.

They’re the processes employees complain about. The applications everyone works around. The operational bottlenecks leadership has accepted. The projects that lost budget battles three years ago because the return wasn’t compelling enough.

Those are the places worth investigating again.

“We Spend Too Much Doing This Manually.”

Manual work has a way of becoming invisible.

A process requires five employees. Then eight. Then twelve. Volume increases, another person gets added, and the cost becomes part of doing business.

But what happens when custom automation becomes significantly more economical?

EXL, for example, built a generative-AI underwriting application in approximately 60 days rather than months. The company reported underwriting cost reductions of up to 80%, while processing moved from days to hours.

The important number isn’t how quickly the application was built.

It’s what happened to the economics of the business process after it was built.

That’s the question leaders should be asking internally:

What are we spending every year to continue doing this manually?


“This Process Won’t Scale With Us.”

Growth often exposes inefficiencies that smaller organizations can absorb.

A manual handoff that works at 1,000 transactions becomes painful at 10,000. A process supported by three people becomes a department. Institutional knowledge becomes a dependency.

Eventually, the constraint isn’t demand.

It’s the organization’s ability to process the demand.

Cosmos Aluminium provides an interesting example. Manual HR and accounting searches that could take days were turned into production applications in approximately 16 weeks. Reported candidate-matching time fell from roughly two weeks to 15 minutes, while the company reported more than a 95% reduction in time spent by HR and accounting teams on relevant processes.

That’s not simply developer productivity.

That’s business capacity.

A useful question for leadership is:

If this business grows 2X, what process breaks first?

The answer may point toward one of the organization’s highest-value technology investments.


“We Know This Application Needs to Change. But the Business Case Has Never Worked.”

Legacy modernization has always been difficult because doing nothing can look cheaper.

Until it isn’t.

The organization gradually absorbs maintenance costs, security risk, workarounds, limited integrations, aging expertise, poor customer experiences, and slower responses to business change.

Meanwhile, replacing the application appears expensive and disruptive.

AI can change portions of both sides of that equation.

Meliá Hotels International modernized a reservation platform with roots going back more than 20 years. The company reported a 60% reduction in compute costs and a 75% improvement in time to market following its modernization efforts.

The lesson isn’t that AI suddenly makes legacy modernization easy.

It doesn’t.

The lesson is that the assumptions behind the modernization business case deserve to be recalculated.

The question becomes:

Is the cost and risk of keeping this system now greater than the investment required to change it?


What If the Opportunity Is New?

The changing economics aren’t limited to fixing existing problems.

They also change how businesses can pursue new opportunities.

Imagine leadership sees an opportunity to create a new digital service, improve an important customer experience, introduce a technology-enabled revenue stream, or fundamentally redesign an operational process.

Traditionally, validating that idea might require substantial requirements work and development investment before anyone could really see whether it worked.

We’ve experienced this firsthand.

Several years ago, we worked with a company bringing a new technology-enabled product to market. At the time, validating and developing the concept required a significant upfront investment and a long runway before the organization could gather meaningful evidence from the market.

If we were solving that same problem today, the approach could look very different.

AI-enabled engineering would allow us to make the concept tangible earlier, explore more options, validate critical assumptions sooner, and potentially reach the market with substantially less time and capital committed before learning what customers actually want.

The opportunity isn’t simply to build the same thing cheaper.

It’s to reduce the time and capital required to get from uncertainty to evidence.

The right question isn’t:

“What’s the cheapest prototype we can build?”

It’s:

“What’s the smartest investment we can make to determine whether this opportunity is real before committing to full delivery?”

A cheap prototype isn’t valuable simply because it was cheap.

A validated solution is valuable because it gives leadership better information about where to invest.


But Should You Build It at All?

This is a question that’s becoming more important - not less - in the age of AI.

The fact that custom software is becoming more economical doesn’t mean custom software is always the right answer.

Sometimes you should build.

Sometimes you should buy.

Sometimes you should configure an existing platform.

Sometimes you should integrate several existing systems.

And sometimes the smartest technology decision is to do nothing yet.

McKinsey’s research into AI-native companies offers a useful way to think about the decision: organizations should consider building capabilities that create meaningful differentiation through proprietary data, expertise, or intellectual property, while approaching more commoditized capabilities differently.⁴

If the capability could create a meaningful competitive advantage, solve a uniquely valuable problem, or enable something your existing technology cannot, custom development may be compelling.

If a proven commercial product already solves 90% of the problem economically, building another version of it may be a terrible use of capital.

The goal isn’t to find a reason to build software. It’s to determine the smartest way to solve the business problem.

And in a market moving this quickly, solid, unbiased advice becomes extremely valuable.


Faster Code Still Doesn’t Guarantee Faster Business Value

Remember those 500,000+ developers?

As AI capabilities increased, coding activity rose by approximately 240%.

Actual releases increased approximately 30%.²

Thirty percent more released software is still a significant improvement.

But the difference between those numbers tells us something important.

The researchers describe what they found as consistent with a “weak-link” effect: accelerating one part of a production system produces diminishing gains if other critical stages don’t accelerate with it.

In software, AI-generated code still needs to be reviewed, integrated, tested, secured, deployed, operated, and improved.

Architecture still matters.

Data still matters.

Business decisions still matter.

The user still matters.

Google’s DORA research reaches a similar conclusion from a different angle. DORA describes AI as an organizational amplifier: it can magnify the strengths of high-performing organizations, but it can also amplify existing weaknesses in the systems around software delivery.⁵

That’s an important distinction.

AI can accelerate coding, documentation, testing, analysis, and other parts of software development. But if the underlying architecture is poor, priorities are unclear, testing is weak, delivery processes are fragmented, or the organization is solving the wrong problem, greater speed doesn’t automatically fix those issues.

It can simply help the organization encounter them faster.

AI doesn’t eliminate the need for good software engineering. It increases the value of it.

And that changes where experienced people create value.

As AI handles more of the mechanical work involved in producing software, experienced engineers can spend more of their time on the decisions AI can’t own for the business: architecture, tradeoffs, security, reliability, integration, user needs, and whether the solution being built will actually produce the intended outcome.

Taken together, the research points toward an important conclusion:

AI can make you dramatically faster at creating code. Turning that speed into business value still requires the right people, practices, and decisions around it.

That’s the gap AI-Fueled Delivery is designed to close.


Yes, You Can Vibe Code It. Then What?

One of the most exciting things AI has done is make software creation accessible to more people.

Someone with an idea can describe what they want and have AI produce surprisingly sophisticated software.

For prototyping and experimentation, that can be incredibly powerful.

But there’s a moment when the question changes:

“Can we build this?” becomes “Can our business depend on this?”

We’ve seen what happens when organizations don’t recognize that transition.

One organization we worked with needed an application supporting an important part of its customer experience. An individual offered to build the solution using AI with virtually no financial risk to the organization: if it didn’t work, they wouldn’t have to pay.

On paper, it sounded difficult to turn down.

But months passed.

The application still wasn’t production-ready. The underlying business problem remained unresolved. More importantly, customers experienced the consequences. The organization lost customers, and an initiative intended to save development expense ultimately created costs in customer trust, lost opportunity, and time.

“Free” software wasn’t free.

The cost simply moved somewhere else.

That’s the risk of evaluating software primarily by what it costs to create rather than by what it needs to accomplish for the business.

AI wasn’t the problem.

The missing pieces were the engineering, architecture, product judgment, delivery discipline, and accountability required to take an idea all the way into production.

That’s why the goal shouldn’t be to choose between AI or experienced developers.

The opportunity is to put AI in the hands of experienced people who know how to turn it into an outcome.


Moving Too Fast Has Risk. So Does Waiting Too Long.

There are two easy mistakes to make in this moment.

The first is rushing.

AI makes it remarkably easy to create something quickly, which can tempt organizations to move from idea to development before the business case, architecture, security, or path to production are clear.

The second mistake is waiting for the market to settle.

It won’t.

The tools will continue changing. Development practices will continue evolving. New capabilities will emerge. And your competitors won’t wait for a definitive moment when someone announces that AI is finally “ready.”

They are already evaluating where technology can reduce operating costs, increase throughput, improve customer experiences, modernize legacy systems, and create new sources of competitive advantage.

That doesn’t mean you need to move recklessly.

It means you need to start learning.

Identify the valuable problem. Understand the economics. Determine whether to build, buy, integrate, or wait. Validate the assumptions. Then invest according to the evidence.

The goal isn’t to move first. It’s to learn fast enough to make the right move sooner.

That’s a very different kind of urgency.


AI Tools Will Become Common. Knowing What to Do With Them Won’t.

Every capable software organization will have access to AI development tools.

So simply saying, “Our developers use AI,” isn’t much of a differentiator.

The more valuable capabilities are knowing which problems deserve investment, which solutions will create meaningful business value, what should be built versus bought, how to validate an idea before overinvesting, and how to move from a promising concept into reliable production software.

That’s where STG’s approach is different.

STG’s AI-Fueled Delivery Model starts before development.

We begin with the business outcome. We determine whether the problem is worth solving and whether custom technology is even the right answer. We validate the solution before committing the full investment. Then we combine experienced engineering with AI acceleration to move it into production - and measure what happens afterward.

We’re not trying to help you build more software.

We’re trying to help you make better technology investments, faster.


The STG AI-Fueled Delivery Model

1. Find the Problem Worth Solving

We begin with the economics.

Where is the business losing money or time? What’s preventing growth? Where are manual processes increasing cost? What is hurting margin, throughput, customer experience, or retention? Where is an aging system creating unnecessary risk?

Then we determine what solving that problem could actually be worth.

This gives technology investment a business outcome from the beginning - and gives execution leaders a business case they can take to leadership.

2. Decide Whether to Build, Buy, Integrate - or Wait

Before custom development begins, we want to know whether custom development is actually the right answer.

We evaluate the business problem, existing technology, differentiation opportunity, economics, risk, and long-term implications.

Sometimes that leads to custom software.

Sometimes it doesn’t.

The goal isn’t to sell you development. It’s to help you make the right technology investment.

3. Validate Before Committing the Full Investment

Once we’ve identified a meaningful opportunity, we use rapid validation to reduce uncertainty.

We can test workflows, explore technical approaches, validate assumptions, put concepts in front of stakeholders, and identify risks before committing to full delivery.

The question isn’t:

“What’s the cheapest version we can build?”

It’s:

“What’s the smartest investment we can make to determine whether this opportunity is real before committing to full delivery?”

The goal of speed isn’t to skip thinking.

It’s to learn sooner and invest smarter.

4. Accelerate Engineering With AI

Once the business case and solution are validated, experienced STG engineers use AI throughout development to increase leverage.

AI can accelerate coding, testing, documentation, analysis, modernization, and repetitive engineering work.

That allows our engineers to focus their expertise where judgment creates the greatest value: architecture, business logic, integrations, security, performance, scalability, and reliability.

AI doesn’t replace experienced engineers. It gives experienced engineers leverage.

5. Get It Into Production

A prototype proves something can work.

Production proves it can work for the business.

STG brings the engineering and DevOps disciplines necessary to cross that gap: automated testing, security, infrastructure, deployment, monitoring, reliability, performance, and maintainability.

We’re not finished when the demo works.

We’re building something the business can depend on.

6. Measure. Learn. Improve.

Production isn’t the finish line.

It’s when we begin learning how the technology performs against the business outcome that justified the investment.

Did manual workload decline? Did throughput increase? Did costs improve? Did customers behave differently? Where is the next constraint?

Then we use those insights to determine what comes next.

Problem → Business Case → Validate → Build → Production → Measure → Improve

That’s the difference between simply using AI to code faster and using AI to accelerate business outcomes.


Think of It Like Growing a Tomato Plant

You don’t plant a tomato seed, water it once, and come back three months later expecting a perfect harvest.

You establish the right conditions. You watch what happens. You adjust. You support growth. You prune what’s unnecessary. And you continuously invest based on what the plant is telling you.

Software should work the same way.

Traditional project thinking often treats production as the finish line: define the requirements, build the application, deploy it, move on.

But that’s when some of the most valuable information becomes available.

Real users tell you what matters. Real operating data shows where value is being created. Real usage reveals the next bottleneck.

AI makes it more economical not only to build software, but to continuously improve it around what the business learns.

That’s how software becomes an asset that compounds in value rather than another aging system the company eventually needs to replace.


The Biggest Opportunity Isn’t AI. It’s What AI Makes Possible.

AI tools themselves won’t create a lasting competitive advantage.

Increasingly, everyone will have them.

The advantage will come from knowing where to apply them.

Which manual process could materially change your cost structure?

Which operational bottleneck is limiting growth?

Which legacy application deserves to have its business case reconsidered?

Which customer problem could technology solve differently?

Which new opportunity could you validate before a competitor does?

Which capability is strategically important enough that you should build it rather than buy it?

Those are much more valuable questions than:

“How do we use AI?”

The better question is:

“What becomes possible for our business now that the economics have changed?”

And once you’ve identified it:

“What’s the smartest way to turn that opportunity into a business outcome?”


There Has Never Been a Better Time to Build

Not because AI can write code.

Because AI can help experienced teams shorten the entire journey from business problem to business value.

We can validate earlier.

Learn sooner.

Build faster.

Get into production more efficiently.

Measure actual outcomes.

And continuously improve what we’ve built.

But greater capability creates a new challenge.

With more things possible, choosing the right things becomes more important.

Moving too quickly can create expensive mistakes.

Moving too slowly can mean carrying unnecessary costs, delaying growth, or allowing a competitor to learn faster than you do.

The answer isn’t hype.

And it isn’t hesitation.

It’s clarity.

Understand the problem. Understand the economics. Determine the right approach. Then use AI’s acceleration where it creates real leverage.

That’s AI-Fueled Delivery.


You Don’t Need an AI Project. You Need Clarity on Your Next Move.

Maybe there’s a manual process you’ve tolerated for years.

Maybe leadership keeps asking when an aging application will finally be replaced.

Maybe you’ve identified an opportunity that technology couldn’t economically support three years ago.

Maybe you’re deciding whether to build or buy.

Maybe your team has already created an AI prototype and you’re trying to determine what it would take to turn it into production software.

Or maybe you simply need someone experienced to challenge your assumptions before you commit significant time and capital.

You don’t need to know the answer before talking to us. That’s the point of the conversation.


Start With 30 Minutes of Unbiased Advice

Start with the question you need answered.

Send us the question - or questions - you want to discuss, and we’ll connect you for a 30-minute conversation with an experienced Executive Technology Advisor (ETA).

This is not a meeting with our sales team.

You’ll sit down with a real person with experience across AI, software development, architecture, and business who can help you think through the decision.

Bring questions like:

Should we build this or buy it?

Does the business case for modernization finally work?

Could AI make this process economical to automate?

Is this prototype ready to become a real product?

Are we approaching this AI opportunity the right way?

Where is the biggest risk we’re not seeing?

We won’t solve every technology challenge your company has in 30 minutes.

That’s not the promise.

The goal is for you to leave with enough clarity and actionable advice to take the right next step.

Maybe custom software makes sense.

Maybe an existing platform is the better investment.

Maybe the idea needs more validation.

Maybe the economics aren’t there yet.

If STG can help with the next step, we’ll explain how.

If we can’t, we’ll point you toward what we believe makes more sense.

Afterward, we’ll follow up to make sure you got what you needed.

No disguised sales pitch. No predetermined solution.

Just an experienced person helping you make a better technology decision in a market that’s changing remarkably fast.

The goal isn’t to move first. It’s to learn fast enough to make the right move sooner.

Talk With an Enterprise Technology Advisor →


Sources

1. Cui, K. Z., Demirer, M., Jaffe, S., Musolff, L., Peng, S., & Salz, T. - “The Effects of Generative AI on High-Skilled Work: Evidence from Three Field Experiments with Software Developers,” Management Science, 2026.

Three randomized field experiments involving 4,867 developers at Microsoft, Accenture, and an anonymous Fortune 100 company found developers given access to an AI coding assistant completed approximately 26% more tasks.

2. Demirer, M., Musolff, L., & Yang, L. - “Writing Code vs. Shipping Code: Productivity Effects Across Generations of AI Coding Tools,” National Bureau of Economic Research Working Paper 35275, revised September 2026.

Analysis of more than 500,000 GitHub developers found progressively larger effects as AI development tools became more capable. The September 2026 revision reports an approximately 240% cumulative effect on coding activity with autonomous agents, declining to approximately 80% for projects and 30% for actual software releases.

3. Gartner - “Gartner Predicts 60% of Organizations Will Adopt Smaller Software Engineering Teams by 2029,” July 2026.

Gartner argues that AI is reshaping software engineering and enabling smaller teams while predicting continued demand for software engineers as demand for software and complex AI-enabled applications grows.

4. McKinsey & Company - “The Seven Operating Truths of AI-Native Companies,” 2026.

McKinsey discusses a build-versus-buy approach in which organizations consider building capabilities that create meaningful differentiation through proprietary data, expertise, or intellectual property while evaluating more commoditized capabilities differently.

5. Google Cloud / DORA - State of AI-Assisted Software Development research.

DORA describes AI as an amplifier of an organization’s existing capabilities: strong organizational and software-delivery systems can turn AI acceleration into greater performance, while weaknesses in those systems can also be magnified. The research reinforces the importance of strong engineering practices and organizational systems around AI-assisted development.

Additional case examples: The healthcare modernization, T-Mobile, Altisource, EXL, Cosmos Aluminium, and Meliá Hotels examples should be verified against and linked to their original published case studies before final publication.

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