I mean, MK has more mass appeal than most of the other fighting games that come out these days. The only people crazy enough to buy a new Tekken game or KoF game actually know how to play fighting games. Plenty of people buy MK who are not at all into the FGC and high level fighting game play.
Many of my friends are not interested in playing any other fighting games with me, including street fighter. But, they will play some MK. And, I've been shocked at the amount of friends of mine who have actually picked the game up and they aren't usually even into fighting games that much.
@hassun: after a while some companies end up bringing out PCB's that you can mod sticks with that support different systems. You've gotta be careful though with PC compatibility. For example even though there are Xbox one controller drivers out now the trigger button equivalents on both of my xbox one sticks don't work on the pc. Doesn't even register they are there.