I don't know what kind of company has got a large codebase and it's taking 20,000 loc pr's expecting that shit to be sustainable, but I work AI first and at the most PR's are touching 12 to 15 files, with the more radical ones sitting at 30. They are still human-reviewable. They are still the kind of change you can revert back to original without breaking all the rest... there are ways of doing this stuff, dear luddites.