Except it ain't free money. Especially when you have viable alternatives like BitBucket and GitLab that are able to operate just fine without ads (well, at least without ads for non-Atlassian products in the former case), the cost is people jumping ship, and git makes that easy to do.

Microsoft would only stand to gain (short or long term) if it's been engaging in its traditional EEE strategy this whole time and is ready to pull the trigger on that final E. Even if that's the case, I can't see any real benefit; it'd just be a middle finger to developers.