I think they mean Linux will be successful in the gaming space in the same fashion it succeeded in the mobile space. The Steam Box will run Linux, no user will ever know about it, and it will leverage the openness of the OS, coupled with the already existing Steam user base to lure developers.

I think this is a game changer for the console game development industry, and for the console market. In the end, however, it'll be a lot like Android: quiet success.