Because the models these games use is not sustainable for all games. Sports games have several things going for them that normal games don't. Like being simulat

Because the models these games use is not sustainable for all games. Sports games have several things going for them that normal games don't. Like being simulations of the real world, so as players move, etc then the game gets updated. Secondly there is an inherint monopoly on sports games. There is only one official NFL game.