Except the point of UWP is to create safely-sandboxed apps that will run on Windows PCs, tablets, smartphones and Xbox One games consoles, so it insulates the software from the hardware.
Good luck if the success of your game requires tweaking the graphics card in a smartphone ;-)
Except PC gamers expect cutting edge experiences like the Oculus Rift -- something they can't get inside the sandbox. That flexibility is the entire reason PC gaming is popular.
Good luck if the success of your game requires tweaking the graphics card in a smartphone ;-)