This is the biggest lesson I got from LMMs. I have a 1 million LOC vibe coded project that I can only imagine would fit in a few hundred thousand lines. But it's still holding up, I expected some kind of development collapse long before this point.
OP is right that code duplication is far cheaper than the wrong abstraction, but the opposite is also true - the right abstraction is far cheaper than code duplication.
Well sooner or later I would expect a developer who intimately understands their code base to feel compelled to start refactoring and extracting fitting, meaningful well-leveraged abstractions.
I don't think that will happen anytime soon. Prompts are the code now, and programming languages code is compilation product. Almost nobody optimizes compiled assembly code.
Perhaps "recompilation" - rewrite by replaying all prompts in strict code quality context (linters, complexity & dedup checks) would make better abstractions.
The only problem now is that LLMs are non-deterministic.
It's made me wonder the same, but most LLM generated codebases haven't been around long enough to judge maintainability. I have noticed issues in some of my more LLM heavy code when I expect a change to be replicated in multiple areas, assuming common code / styling was reused, only to find it wasn't. It's for that reason I can't use LLMs for client codebases without heavy scrutiny of every line generated (for my own hobby projects I'm a lot more lenient)
