There is a seductive story going around: that AI has made building software essentially free. Describe what you want, the machine writes it, and you have an app at no cost beyond a subscription. It is half true, which is what makes it dangerous. The cost of producing code really has fallen dramatically. But “cheaper to produce” is not the same as “free to have,” and the difference is where people get hurt.

The costs did not disappear. They moved, to places that do not show up on an invoice, which is precisely why they are easy to ignore until they arrive.

What genuinely got cheaper

Let us be fair to the story first. Generating a working first version of something is faster and cheaper than it has ever been. A capable person with these tools can stand up in a weekend what used to take weeks. For prototypes, for trying an idea, for the rough first cut, this is a real and wonderful change. If all you need is to see whether something could work, the barrier really has dropped close to the floor.

Where the cost actually went

The trouble starts when “a working first version” gets mistaken for “a finished product.” The gap between them is where all the cost quietly relocated.

• Judgement. Knowing what to build, and what to leave out, has not got cheaper at all. The machine will build whatever you ask, including the wrong thing, very efficiently.
• The unglamorous 80%. The demo is the easy 20%. The error handling, the edge cases, the security, the thing working reliably on a bad day for a real user — that is the bulk of the real work, and it is the part the quick build skips.
• Knowing if it is any good. AI will happily produce code that looks right and is subtly wrong. Catching that requires someone who can tell the difference, and that ability is not free.
• Maintenance. Software is not a thing you build once. It is a thing you own. It needs updating, fixing and adapting for as long as you rely on it, and AI generating the first version does nothing to remove that.

The trap of the 80% demo

The specific way this bites is brutal and common. You get to a working demo astonishingly fast, and it feels like you are nearly done. You are not. You are perhaps a fifth of the way to something you can actually depend on. The speed of the early stretch sets a false expectation for the rest, and the last, hardest, least visible 80% — the part that decides whether the thing is trustworthy — proceeds at roughly the pace it always did, because it was never the part AI made cheap.

The result is a particular kind of stranded project: cheap to start, expensive to finish, abandoned in the gap when the true cost of “finished” finally becomes clear.

What this means for you

None of this is a reason not to build with AI. It is the most powerful way to build that has existed, and used well it genuinely lowers the cost of good software. It is a reason to be honest about what you are buying. If you need a quick prototype to test an idea, the near-free story is more or less true, and you should take advantage of it. If you need software a business will actually run on, budget for the judgement, the unglamorous 80%, and the years of ownership, because those costs are real whether or not anyone put them on the quote.

The cost of building did not go to zero. It changed shape, and moved to where you cannot see it. The people who do well with these tools are the ones who know exactly where it went.