How does post-training via reinforcement learning factor in? Does every evaluated judgement count as 'the training data' ?

Firstly, it doesn't really matter if they can produce novel designs or not. 99% of what is being done is not novel. It is manipulating data in ways computers have been manipulating data for decades. The design of what is implemented is also going to be derivative of what already exists in the world too. Being too novel makes for a bad product since users will not easily understand how to use it and adapt their existing knowledge of how other things work.

Secondly, they are able to produce intelligence that wasn't represented in their training input. As a simple example take a look at chess AI. The top chess engines have more intelligence over the game of chess than the top humans. They have surpassed humans understanding of chess. Similar with LLMs. They train on synthetic data that other LLMs have made and are able to find ways to get better and better on their own. Humans learn off the knowledge of other humans and it compounds. The same thing applies to AI. It is able to generated information and try things and then later reference what it tried when doing something else.

This is humans have traditionally done with greenfield systems. No choices have been made yet, they're all cheap decisions.

The difficulty has always arisen when the lines of code pile up AND users start requesting other things AND it is important not to break the "unintended behavior" parts of the system that arose from those initial decisions.

It would take either a sea-change in how agents work (think absorbing the whole codebase in the context window and understanding it at the level required to anticipate any surprising edge case consequences of a change, instead of doing think-search-read-think-search-read loops) or several more orders of magnitude of speed (to exhaustively chase down the huge number of combinations of logic paths+state that systems end up playing with) to get around that problem.

So yeah, hobby projects are a million times easier, as is bootstrapping larger projects. But for business works, deterministic behaviors and consistent specs are important.

> in a couple years when models are significantly better.

They aren't significantly better now than a couple of years ago. So it doesn't seem likely they will be significantly better in a couple of years than they are now.

For now I would be happy if it just explored the problem space and identify the choices to be made and filtered down to the non-obvious and/or more opinionated ones. Bundle these together and ask the me all at once and then it is off to the races.

And I'll say it doesn't matter. If it goes with your approach then I'll say that the approach works too. And if goes with my approach I hope you would recognize that my approach also is good enough for what we need. As long as the software meets the requirements, its okay if it isn't implemented the exact way it would have been if it was done by hand.