I'm sure it works both ways. If Github was somethingelseHub, somethingelse would be popular. Git started gaining popularity thanks to great UI and communities on github and gitlab.
Another big factor contributing to it's popikaroty was that the Linux kernel (that even when git came out was a pretty big codebase already) also used it to great success.
The only real credit that can be given to GitHub in my eyes is that it allows individuals to more easily host remote repos.
GitHub launched in Feb 2008, Git soared and SVN plummeted.
https://trends.google.com/trends/explore?date=all&q=%2Fm%2F0...