This is the brake on “AI will replace all developers”.

Coding is a correctness-discovery-process. For a real product you need to build to know the right thing. As the product matures those constraints increase in granularity to tighter bits of code (security, performance, etc)

You can have AI write 100% of the code but more mature products might be caring about more and more specific low level requirements.

The time you can let an agent swarm just go are cases very well specificed by years of work (like the Anthropic C compiler)