albino boo said:
They are a major retailer but not a major producer. Valve haven't put out a AAA title in years and only have 2 franchise to their name. For SteamOS to be successful its going to need some of the major franchises from EA, Activision and Ubisoft to be ported.
Unless we count The Sims (a game targeted at those outside the Steam OS target audience anyway), none of those 3 have a game that outsold Half-Life 2 (and only one that outsold Half-Life, which was released in 1998 before Steam existed) on PC.
Blizzard has put up a few better selling titles (and they are kind of part of Activision now) but they're now rapidly pissing away their reputation for quality with PC gamers due to some recent products being awful, and it would be a bit surprising if they manage another Diablo 3. Plus Blizzard doesn't use Steam now, so there's no way they'd use Steam OS unless it became super popular (they'll probably never use a third party digital distribution system given their own network). Plus Blizzard puts out sequels even slower than Valve does.
If Valve is aiming where I think they are anyway, their objective will be to build up on indie titles and their own products (possibly HL3) -- much the same way Steam was until around 2007 when they got some big devs along for the ride with some big releases (having carried it on the back of Half-Life 2 and indie titles until then). Plus if they can put out an easier to work with mechanism than DirectX, some devs will go for it due to the sheer simplicity.
Also worth noting that EA DICE already expressed some interest in Steam OS.