But I wonder if I can add one more possible reason for the lack of discussion, perhaps related to the valid "games aren't taken seriously yet" point. The demographics of the average gamer. I confess I don't have the statistics, but considering just how much these new systems cost (I certainly can't afford them), I'm willing to hazard an educated guess that it's largely middle-class children and adults who have, in addition to disposable income, disposable time. That demographic, I think, is not the one most inclined to think about issues such as racism, sexism, and heterosexism in their daily entertainment.
This is one of those times when someone says something that makes total sense to me, and makes me go "Duh! How did I not realize that sooner?" Video gaming has been, since the start, a largely middle-class hobby. With systems that cost hundreds of dollars, and games that generally come in over $40 when they're released, it makes sense that there's going to be cultural lag. I've seen age breakdowns and sex breakdowns on who is playing games. I wonder if someone has done racial and economic breakdowns, too?
Anyway, I think air is on to something with this.