Lookup the history of GVFS and why Microsoft chose Git. There are interesting reads about it.
There's also lots of interesting reads about 'monorepos' and their pros and cons. Note tho that Google and Facebook, and lots of other companies, use mono-repos. It's not just Microsoft and, not surprisingly, they've all made (more or less) reasoned, thoughtful decisions taking into account lots of factors that almost no one else in the world would ever think to do.
There's also lots of interesting reads about 'monorepos' and their pros and cons. Note tho that Google and Facebook, and lots of other companies, use mono-repos. It's not just Microsoft and, not surprisingly, they've all made (more or less) reasoned, thoughtful decisions taking into account lots of factors that almost no one else in the world would ever think to do.