Well they could change the terms of service and essentially drive certain types of projects away. They could limit access to older builds and versions to non-paying customers. They could limit access to verified/signed builds. They could reserve certain rights to your software such as they did with npmjs.com. They could run ads, offer IT staff skill matching and promotions, FizzBuzz-like services, or other LinkedIn integrations. They could come up with clever schemes for offering commercial licensing for open source. They could go after the enterprise package mirrors and policy checkers market Artifactory et al are serving. Not saying they'll be doing that (MS isn't stupid), but given MS is selling mainly to enterprises, there are many creative ways they could make money of it.

Seeing they don't do any of that today with VSTS there is no basis to believe they would do that for Github.

What do you mean deploy to "GVFS"? VSTS -Microsoft's existing host solution supports the standard git web hooks today to support integration with third party CI/CD tools and supports Azure and AWS deployments.