It helps that beyond critical fixes the kernel doesn't really have deadlines so there's time to be extremely picky about the code and commits. I think a lot of

It helps that beyond critical fixes the kernel doesn't really have deadlines so there's time to be extremely picky about the code and commits. I think a lot of cruft and bad code comes from time constraints from business, not all for sure but a lot. And beyond that as an OSS project going back and rewriting things doesn't cost anything (at least in real money) so there's not an economic pressure against going back and addressing cruft.