I don't know, Android is a Linux derivative and these days it basically owns the mobile gaming market and is the fastest growing gaming platform basically ever. Also many of the issues you highlight with Linux derived builds were apt four or five years ago and not so much these days. Plenty of Linux OS versions that work reliably out of the box and that trend is only increasing now more hardware manufacturers are working with hardware primarily designed to interface with the Linux kernel.
Not even going to lie, I don't exactly keep up with Linux developments, so my info on the quality and driver support is probably dated, but most of the other stuff I said still stands. Even if the OS becomes largely successful, it only stands to improve gaming on Linux-based systems.. It does nothing for a PC gamer who is content with Windows except I guess potentially scaring Microsoft into shying away from policies that try to force you to upgrade your OS like locking Direct X11+ from XP, and locking Direct X11.1 to Windows 8 and such. That would admittedly be great, but it's the only real change you'd experience if you didn't want to change your OS.
For a person that wants to keep the extensive library of gaming and non-gaming applications that Windows already provides, as well as the more casual user who wouldn't want to ever fiddle around with having to find drivers or worse yet, finding out that the program they want isn't supported, there's really no reason to hop over to the SteamOS.
Finally, as everyone's been speculating for 2 years now, Valve just announced the Steam Boxes (Steam Machines), and it's even clearer that this Steam OS isn't supposed to revolutionize PC gaming, it's to revolutionized CONSOLE gaming, and bring them both closer to singularity.
See if Valve can win big in the living room with a "console" that is 100% a computer, then people will come to expect that quality from all the other consoles, and they'll have to provide it. That is a huge hypothetical however because I don't think the average casual joe who only buys COD or GTA for their console knows jack sh*t about Valve, or cares. Valve may be huge for PC gamers, but to your average console player who only owns a macbook? They don't even exist.
They pretty much have to pull an Xbox, without the "being a household name like Microsoft" part. That's going to be hard as f*ck to do. The way it would have to go down is to put out some serious marketing dollars forward. They have to show people that this isn't the console they're used to:
Upgradeable parts that you just snap in!
Actual programs! (You know Firefox/Chrome/Opera that you use on your computer? We got that sh*t right here!) This is YOUR console, use it how YOU want to! (YEAH!)
Optimized games that look better and run faster than any other system on the market!
Finally they need some kind of huge exclusive system seller.. Something like Halo was for Xbox. Half-Life 3, maybe.
If that goes off great and gets a chunky install base, eventually, with some help from developers then you might have something where Sont/Microsoft have to put out their own open platforms or die... If the casual gamer will even stomach such a system.
With the way they have this thing set up, anyone can make hardware at any time for a Steam Machine, or make a whole new Steam Machine, more and more hardware manufacturers will start pushing out Steam Machine hardware including short cutters using shoddy parts, all of a sudden you have 4 different ATI steam machines, 2 Nvidia steam machines, an Intel steam machine, Gigabyte has theirs, Rosewill whoever, some random Chinese company uses 4th world parts... Now you have Steam Machines with all kinds of prices from $300 monstrosities to intimidating $1300 enthusiast boxes, as a casual gamer isn't that exactly what scares them away from PCs? Isn't that the exact kind of thing they pay NOT to deal with? Macs aren't popular for no reason.. Consoles didn't get this popular for no reason. They pay to not have to ask questions at the check out counter.
Which one do I buy? Are the parts going to be compatible? The $600 one looks good, but how long will that last me? Will I have to upgrade in 3 months? Oh look the "Steam Machine 2.0 CPU with 6 cores, running at 3.2ghz, with 16 gb ram, and Nvidia GTX 880M..." BLAH BLAH BLAH, what the f*ck is this sh*t?
For those reasons, I'm interested in exactly how Valve plans to sell affordable gaming PCs to the casual market, while not only avoiding all of those problems, but making a profit and establishing dominance as well. At the end of the day, a market with only PC-based open platform machines sounds like great idea, but there will always be a market for closed platform boxes. Why buy the "ATI Radeon Windstorm Pro Steam Machine 8GB version" for $800, when I can just pick up a Playstation 5 for $600 and be for the next 7 years?
I know why, and you know why, but not only does the average gamer NOT know why, they don't even care.