Some games are more suited for the intimacy of the PC, and others are best played from the couch in front of a larger TV screen. We ultimately realised that the way we'd make the most money was to sell Alan Wake for £40 on the 360 instead of £25 on the PC, so we focused on making it an Xbox 360 exclusive. Both Microsoft and Remedy have long histories in PC game development. This decision was about Remedy accepting our £'s to make the game specific to the Xbox 360.
At least they're honest.