I wouldn’t worry too much. UWP was mostly meant as another attempt for MS to finally make some money in the smartphone market, and that’s failing hard. Again. Nobody is developing for Windows Store. And people certainly don’t want another store for PC games outside of Steam, except maybe those anti-DRM evangelists that are already snatched up by GOG.
Can’t blame MS for trying. Apple, Google and Valve are doing it. Oculus hopes to do it for VR games.