[aryastark]

I don't think porting is the main issue, with Linux adoption. It's always been support. You extend to another platform, you're instantly responsibly for all the tech support of your game on that platform.

IIRC, id Software pretty much had a "you're on your own" type of deal, with people using Linux. They provided the Quake binary, gave a README and some FAQs, and then you're on your own.

Likewise, Blizzard does not allow people to run World of Warcraft on platforms other than Windows and OS X. They know people run under WINE and could prevent them. But they don't. They just don't support it. It's win-win for them. More users without doing anything.

Porting is pretty easy if you target OpenGL and keep everything (sound, input) generic. SDL also works on many platforms.