The year is 2019.

C++ is still one of the most powerful programming languages around..............with no centralized package manager that is widely adopted by the community that allows one to sandbox libraries from conflicts with one another.

I ain't hating, just find this funny and I love cpp

Apt get/git submodules it is!!

For some reason github is returning 503 on our build servers randomly. And I need to checkout several repositories to build everything successfully. Builds are automatic and I don't want to maintain local mirror. And we wanted to release tomorrow (but were smart enough to promise this week). And on top of everything build takes six hours and sometime fails randomly even without github. But I'm still optimistic - it's Monday after all. We still have enough time to make it in time for Friday release :-)

Git was designed to be used in a decentralized fashion, and as such has a lot of additional logic steps to deal with this.
The way people use git today only with centralized storage such as github makes it a inferior solution compared to SVN