Edit: I misunderstood your comment as about Azure generally and not Azure DevOps specifically. I see Azure DevOps as the “full service” version of GitHub’s slightly more “DIY” approach. DevOps can also be customized and sold by partners, consultants, I think. GitHub if anything, might move more to a “consultant network” approach. I think Microsoft is maintaining two district brands for developers, for the time being. I originally wrote:

I think there’s a clear benefit to Microsoft for GitHub to internally use Azure, but I think there’s a clear benefit to Microsoft’s developer community, GitHub and the Microsoft Partner ecosystem for GitHub to support AWS and GCP via open source, AWS Marketplace, Docker and anything else that helps ensure GitHub is useful independent of the rest of Microsoft’s services — GitHub being impartial is more important to Microsoft than the extra market share they might — might — get.