In a recent poll, less than one percent of Steam users are using Linux and Unbuntu combined. If we throw in Mac we get 3.5% using that platform, most everything else is Windows. Window 7 with DX 10, Windows 8 with DX11, Windows 8.1, etc., it is still all sorts of different kinds of Windows. Windows might not be the best at everything, but it does quite a good job a gaming, working with all sorts of hardware, and different kinds of input, and developers like it. And soon, it much of it will be updated to Windows 10 and many to DirectX 12. This will add game DVR fuctions to everyone's PC (Like on the Xbox One) and other cool features.
Right now many people are requesting Half Life 3 and many other games that Valve is known for, but rather than work on those games instead they are developing their own operating system. Valve is developing SteamOS, which is a gaming system - like Windows/DrirectX that is going to be used to challenge Microsoft as a platform. The problem is they need outside vendors, i.e. 3rd party developers to make any real dent. Now if it works say 10-20% better than Windows/DirectX, then I could see that actually happening. But it seems very unlikely and that's a rather low bench mark. Compounded by the fact than so few people run Steam on anything but Windows.
So they really have their work cut out for them. It's a huge gamble and may pay off well, or be a colossal waste of money, time, talent, and man power.
What, if anything, do you think Steam could do, or specs they need to hit, to make SteamOS a real contender for gaming, developing, and control over the living room?
Here is the survey for the curious: http://store.steampowered.com/hwsurvey