What we are seeing now is Microsoft reacting to being kicked out of several markets by going back to the embrace phase in an attempt to regain some of the ground lost from Balmers failed attempt to secure a foothold for MS in the mobile and web framework markets.
If they had really been about embracing open source and open standards we would have seen them do something useful for Linux like releasing a version of excel for Linux or opening up the protocols outlook and exchange use to talk to each other, but that kind of openness was never on the table.
What i would expect to see with github is that if/when ms decide they want to utilize their investment for profit is a heavy integration with the azure environment in the form of CI hooks designed around azure api's to the point where other CI platforms become 2nd degree citizens in the ecosystem and i would not be surprised if a github account becomes a add on to an office365 subscription rather then a stand alone product.
If you told me 5/10 years ago about these developments I would have never believed you.
I don't think it's fair to reason about a (40+ year old, 100k+ employees, public) company's behaviour as if it has a mind. It doesn't.
[0] https://www.zdnet.com/article/top-five-linux-contributor-mic...
[1] https://github.com/Microsoft/vscode/blob/master/CONTRIBUTING...