How many(Those who have ATI hardware) Windows users are gamers?
you can't deny that Windows is wat GREATER OS for gaming
Furthermore ATI and nVidia have this thing called "unified architecture". Furthermore ATI drivers are there... just bugged. And third... video playback is used a big time more than actual gaming on Linux or Windows.
And finally Linux is no more a great minority. After all even Microsoft recognized it as a force to reckon with and PC vendors consider it as OS to preinstall. I don't think a "great minority" would have achieved this, not?