Echoing other thoughts here but also, it's like getting your first 10,000+ lines of output code for 0 token cost, and no prompting effort, no back and forth or testing etc.

Just jump straight to business logic, scaffolding is done for you already.

I think in your question as well is an idea that apps from now on will be bespoke, small and unique entities but the truth is we are still going to be mostly solving already solved problems, and enterprise software will still require the same massive codebases as before.

The real win of frameworks is they keep your workers, AI or human, constrained to an existing known set of tools and patterns. That still matters in long term AI powered projects too. That and they provide battle hardened collection of solutions that cover lots of edge cases you would never think to put in your prompts.