Second, even if you do the first, the whole thing gets screwed up again when you start trying to introduce vendor code into the mix. Generally, no one upstream gives a crap that you have super compelling business reasons to compromise on code quality (or even trivial things like how code is committed: tarballs vs good git hygiene), and vendors sometimes compromise a lot.
So it’s not surprising that sometimes groups choose to do the expedient thing to get something to market instead of doing things “the right way.” In a lot of respects, the original Android did this with Linux.
Competition is good.