I'm not sure I understand fully. Here is my take.
What is stopping 3rd party developers from putting the game on Windows 10 store and Steam? I thought UWP could be used for also making games and releasing them on IOS, Android and Steam? It just makes it easier for A developer to make it available for MS platforms. I didn't think it stopped a dev releasing on rival platforms.
The only thing I see MS leveraging is its exclusives. Which surely they are entitled to do? No?







