Sure, it's possible they're actively getting more developers to create games for Mountain Lion, though that is pure speculation at this point. Gaming is already nicer on OS X than Windows, at least with the games I tried, because you can put most of them in window mode and put them in the background to check your mail and such. With some modern games that's still not possible on Windows. And they should work beautifully in conjunction with the new fullscreen = separate space paradigm.