Damn right it's important to them. PC gaming on Windows is what props up their whole house-of-cards business model. As others have already said, if it wasn't for Windows' monopoly on PC gaming, the Windows client OS would not have anywhere near the desktop market share it currently enjoys. And if you don't believe me, take a look at the server market and ask yourself why MS have failed to achieve the same market dominance. PC gaming is the only reason people choose Windows. Full Stop. The alternative OSes are as good, if not better, at doing anything else and they're a damn sight cheaper.