Apple does take gaming seriously. They've built out comprehensive Graphics APIs and things like the GPTK to make migrating games to Apple's ecosystem actually not too bad for developers. The problem is that a lot of game devs just target Windows because every "serious" gamer has a windows PC. It's a chicken-and-egg problem that results from Apple always having a serious minority share of the desktop market. So historically Apple has focused on the segments of the market that they can more easily break into.
