I think I read somewhere that game dev teams would also check in the actual compiler binary and things of that nature into version control.

Usually it's considered "bad practice" when you see, like, and entire sysroot of shared libs in a git repository.

I don't even have any feeling one way or another. Even today "vendoring" cpp libraries (typically as source) isn't exactly rare. I'm not even sure if this is always a "bad" thing in other languages. Everyone just seems to have decided that relying on a/the package manager and some sort of external store is the Right Way. In some sense, it's harder to make the case for that.