That's just so inefficient and wasteful. Assuming a world in which LLMs do most of the coding work, do we want to burn electricity having the LLM build an options dialog or config file parser once, or do we want to burn electricity millions of times as users want to change any little thing about the software they use?
I really hope what you should expect is my answer to that question isn't controversial.
Having an LLM do bespoke customizations that are unlikely to be interesting to other people? Great, sure. But adding a generally-useful feature to a piece of software, but not caring to try to upstream it? Lame. Lame, lame, lame.