More QuakeCon wrap up stuff, over at Linux Games there's an interview with id's Timothee Besset, who's the guy who currently maintains the Linux ports of Q3 and RTCW and the Q3A level editor as well. It mainly focuses on previous id games such as those mentioned, but there are tidbits about Doom 3:
Besset noted that, looking back, id has always been basically the only company that's always been there for Linux, pushing for better hardware support and willing to maintain multi-platform code. He hopes that DOOM III would help convince other companies that similar ventures are worth it in the long run, as the porting process itself helps Quality Assurance teams track down general bugs that only become readily apparent on another OS, and having solid code is in the best interests of all parties involved.
So there you go. Yay Loonix!