I don't think it's necessary for GitHub to exist, or be owned by Microsoft, for open source efforts to be exploited in the manner which you describe. OTOH, I'm

I don't think it's necessary for GitHub to exist, or be owned by Microsoft, for open source efforts to be exploited in the manner which you describe. OTOH, I'm unaware of any hard data regarding just how much open source work is done at the behest of commercial interests, and without compensation. Come to think of it, that might violate minimum wage laws in some countries.