Well yes, if a team doesn't bother to understand the code, that's certainly quicker.
People should have read to the end of "Building a C compiler with a team of parallel Claudes"[1]:
The resulting compiler has nearly reached the limits of Opus [4.6]’s abilities. I tried (hard!) to fix several of the above limitations but wasn’t fully successful. New features and bugfixes frequently broke existing functionality.
"tried (hard!)" is very ominous. I wonder how Mythos would fare. Presumably it would get further, maybe much further. But I strongly doubt the "frequently broke existing functionality" problem was solved. Eventually humans have to understand the most difficult parts of the code. Good luck with that![1] https://www.anthropic.com/engineering/building-c-compiler