Git is objectively better than Subversion. The problem is we are conflating a widely used hosting service with the underlying SCM. We don't need github to use git successfully. Sure, it's nice, but you can install Forgejo or something, which is the exact same boat we were in with Subversion + Trac. You can have that experience right now if you want to.

What github is good for is discovery, getting contributions on open source projects (because it's so popular), and integrations. If you wanted to, you could host your open source project on Forgejo and use github as a mirror just to benefit from the visibility and get contributions.