amok: The main difference is that Valve does not set itself up to be a monopoly Strijkbout: Steam OS says hello.
SteamOS has nothing to do with monopoly and everything to do with reducing the amount of configuration the user must put in to get games to work as well as insulating themselves from the very transient and volatile nature of most open source platforms out there including the major ones (which has implications for reason 1).
I have Steam on Debian. it didn't work. had to run my mannly hands over it to get it cooperating.
I have some games installed on my Debian Steam. they did not work. had to do some more things, but at least I was able to do them to get games running. Linux, after all, is all about being a freeman.
Point is, I have games installed on Debian and it did not go smoothly. SteamOS is all about dealing with that, but it's not the same thing as monopoly and trying to be what Windows is trying to do.
also, Valve needed to improve the backend of Linux for the purpose of running games, something Linux doesn't really put a ton of focus on or at least historically didn't, and SteamOS was there way of ensuring that stuff got used.
and also, the UI guys would be like "it has to look and feel the same!" and the marketers are like "it has to all be branded!". fuck those guys. well not the UI guys.
in fact, just in case anyone from Valve is reading this. holy jeez Steam looks great lately. especially the website. just looks great. this transparent gradient stuff. when I went to mint's website when that happened, I noticed they were doing it too. I dunno if they were doing it first or you were but it just looks great. Patrick Klepek once said UI design is not Valve's strongsuit and at the time I didn't know what the fuck he was talking about. it was a rare moment where he was off point. cause Steam looks great.