In this case it's also a hardware issue. If smartphones ran x86 I'm sure some clever hackers would've found a way to boot windows on them and from there you could play any game you like. But being ARM it's pointless.
first, there were tons of x86 android devices. samsung tab3 to name the last one i used.
second, most of the code on android is tainted GPL code. technically GPL was supposed to not prevent you from running whatever you want on devices you own if it was distributed with GPL based code, but alas, that is exactly what happens.