It's really bizarre reading the irrational hatred of being offered a choice. What does it hurt you guys if Linux is an option? Personally I'd love to get away from MS.
As to Carmack: They haven't shipped a good game since Quake 3, and in those days their idea of supporting Linux was to release the game for windows, put a Linux binary on their FTP, and then wait a few months before putting out retail copies of the Linux version. Was he really surprised that no one waited that long, and just bought the Win version and used the binaries from the FTP?