I think Actiblizz', Valve's, and the other bigger game companies' new found love for Linux is a bluff. IMO they're trying to put some pressure on Microsoft to rethink its Win8 market place. I really don't think the big game companies want to irritate their customers with Linux and its not very consumer friendly "compile your own files" approach. Yeah, I know, it's easy to use for nerds, but we're talking the Average Joe Steam customer here.
Nerd Here taking a guess you never tried Ubuntu. 99% of Ubuntu user don't even know what the heck compile means. My wife and teens use it all the time. They don't even know it is Linux.