This. Github's enterprise base is at least partially a subset of their open source population. If Github doesn't keep OSS momentum for their product, they lose the perceived "default client" status to git repositories. OSS and eventually enterprise starts looking elsewhere.

This is getting more and more relvent since solid competition is starting to crop up everywhere. Gitlab, Bitbucket, GOGs, Gitolite, Gerrit. Not apples to apples of course, but Enterprise has a lot of decisions when it comes to git control.

Even the things that could be considered Github "lockins" aren't really so: Google's git-appraise[0] could make pull-requests portable, Github's wikis are portable by their very nature[1], software like git-issues[2] could make issues portable. Not in the immediate, but decentralize-everything is a rising sentiment.

The only real lockins I see are Github's work-flow and social community. If either become toxic, developers will start to look elsewhere. Like Microsoft, I'm sure Github can ride the majority-player wave for years before it starts really hurting them, but simply saying a community-centric company only has to look out for their paying community's interests is short-sighted.

[0] https://github.com/google/git-appraise [1] https://github.com/gollum/gollum [2] https://github.com/duplys/git-issues