To be honest then I think its a miracle that anyone doing games where the majority of their sales come from consoles can be bothered with porting them to PC anymore. Although probably hard to really prove anything, then I think the general trend is that a lot of hardcore gamers with a decent rig will always pirate the games they can on PC and only buy the console exclusives because they're forced to it.
Then again, there's still a market there, especially for something such as MW2, question being if you'd get more legit people than you'd lose by doing a PC version ![]()