Like they've been holding back the development of games for years? I have a Mac for work, and it's good at what it does. But I wouldn't choose one for a home/personal PC. The lockin and limitations aren't worth it (not just for games, generally). It would be like using IE6 for web browsing.

If they choose to not keep up with web development, that's not going to hold web development back, it's going to hold Apple back, and make them obsolete. Currently, they have a good share of the 'devices used for web-browsing' market, but if they don't keep up, it'll dwindle to match their share of the gaming PC market.