That seems very unlikely. Github is the entire reason git is so popular, vs. any of the other distributed VC systems.
Edit: I'll refine that, after a moment of thought. Git is popular because of Github. But, I guess that now maybe there are people who are using git because it's the popular/default version control choice, but they might not be using Github. They might be using another forge, something homegrown, or just manual builds.
Github was like Yahoo's directory, a way to share content in a searchable place and as a backup/bounce point. In the early days you could also upload to 'downloads' so it was a quick share host. Before that we had email, exposed ssh and cgit/gitweb but Github gave us `PR` to promote social interactions with forking. So it could be argued that Github tainted the spirit of git.
Having personally evolved from making date stamped zip files, to subversion and then to git, it earned its place quite quickly for myself and my roaming nature, didn't hurt who hacked it together either. When Linux adopted it from Bitkeeper, it became the way for many.
Personally I prefer GitLab over GitHub. The CI is better, and it doesn't go down every other week unless you self host on Azure.