To me, this is an issue of platform independence - DirectX may be all kinds of awesome for game development, but if it only works on one platform, then why limit yourself at all? Another example would be if I developed a webpage and said, "Well since Internet Explorer users only make up 10% of the market, I'm not going to bother supporting it." If I had this attitude, I wouldn't be in business. Secondly, I disagree with the notion that there is a limited market for Mac gamers - I think (and feel free to correct me if I'm wrong) MOST Mac users are young people and MOST young people play games. You want to know why I don't play very many games on MY Mac? Because there AREN'T very many games for my Mac. This argument seems entirely circumstantial. Not to mention that Apple is growing and growing while Microsoft is struggling to remain relevant.