If Valve went for the corporate market, then, maybe, yes, but I think MSFT has always made most of its OS money on corporate stuff (home users often use Windows, because that's what they work with).

Gaming isn't really a thing, with corporate use.

I use a Mac. Macs are some of the worst gaming platforms on Earth. If I'm lucky enough to get an AAA game, it's seven years behind its PC version, and a huge bug farm.

SteamOS might actually get me to consider a console, but gaming hasn't ever really been a priority for me (obv.).