It is like people just can’t not to vendorlock even with git.
Eh, they provide a useful service. I wouldn't want to run my own git server.
Its not like that's something that will scale infinitely, you only have so many devs and so many repos to work on, also it's not like it's hard to backup the data, actually, you can bet that you will have a updated copy of every repo on someone's machine if things really go south.
Of all things we can outsource in our infra, git seems one of the least necessary.