I'm still trying to figure out why having everything dumped in one big pile is something worth bragging about. I'd far rather have code sorted well into proper repositories.
So much is shared, though, right? Which is why Android is sorted into proper repositories but still has the 'repo' front-end wrapper to make sure you're getting the right versions of everything you need.
If I wanted to change something fundamental, like I found a 10% speedup in Protobuf wire decode by changing the message slightly, there are likely very many services that all need it.
Everyone at Google operates on HEAD. You're not allowed to break HEAD, and pre-submit/post-submit bots ensure you don't and will block your submit.
From my perspective, at least, this design seems to explain why Google websites are so frequently broken in the ways different services integrate. Because Googlers edit shared resources that affect products they don't personally work on, and they just trust automated tests, which almost certainly miss a lot of the edge cases I encounter.
I admit that I'm not an expert at large software development, but this seems to nearly fully explain Google's declining code quality.
