Wow, that's optimistic! I'd be happy if they just keep it neutral.
Fact is all the big vendors publish and collaborate on github, this purchase threatens that ecosystem. And we are more likely to see a message of private code hosting sites, than a solid federation system for source control.
I think at this exact moment, there is a really interesting space that can be filled by a FOSS Github alternative. I think a new player might be better equipped to offer it. Maybe someone can build something off of Keybase's git services.
I am sad to see an independent voice go, but I don't think Github has been able to stay competitive and IMO this could be a good thing. That remains to be seen, but regardless of Gitlab's ability or what MS might do, I think there is a vacuum left that I'm hoping we can fill as a community and I'll put my effort and dollar behind whatever shows up to do it.
Someone should ask Linus what he thinks about git federation. Maybe he can save us from ourselves again.