Current agents never take a step back to refactor and to create a good abstraction as the requirements evolve, they only care for delivering fast even at the price of garbage code which doesn’t scale
Certainly, it would be super super difficult to generate training data for it, so it's unlikely that it will improve.
Because of the scale that would be needed. Like, design stuff is much fluffier than code correctness or functionality, so really really hard to generate enough synthetic data to tune the models to do better.
In the limit yeah it would work, but in the limit we're all dead ;)
I e., a responsible developer who cares about quality will have to get their hands a little dirty with some maintenance now and then.