I think Unix/Linux does a good bit to help Valve and others, and not only run their businesses, but basically keep their 24/7 incredible profit generating services going. Enough people have asked for Linux support from Blizzard, Valve, Rockstar, Bungie, etc..., and for the amount that these companies depend on Unix/Linux, they have more than enough resources to release Linux versions, as a way of acknowledging the free OS.
Blizzard and Bungie made Mac versions of their games, because they wanted to. But I think we'll find that it's important to thank and give back to what you use and depend on, and in this case that means Linux games. Just watch