Its dirt simple (Score 1)

The game maufacturers only need one inducement-- money. There is no Linux game support because there is not a large enough Linux game buying public. At over 5% of the market, the Mac gets minimal support. At less then 1% of the desktops, Linux isn't a contender. Plus a large majority of those desktop users run Linux because its free and don't want to pay for software. But its wrong to say Linux users aren't gamers. I have 2 Linux systems in my house and Im a gamer, I just don't game on the Linux boxes. I have a Win XP box, an XBox360 and a PS3 for that.