Never mind the fact the controller issues will be abundant - and the game selection won't be the same and that there will be updates and issues and everything known to windows appearing out of nowhere.
Why would controller issues be abundant? Why would there be any controller issues at all? Game selection would be greater. How is that a problem? Problems with updates are rare overall and are easily fixable as are all PC related problems. At the worst, you'll have to replace components, which are readily available for purchase. So, if the warranty has ran out, you can still repair the PC easily and cheaply without any hassles finding parts. What do you do if your console develops problems and the warranty has ran out?
Your inviting User Errors into the home - by a SFF PC.
PCs and laptops are already in the home. Everyone I know has a laptop, most of them have consoles, a few of them have PCs and a few have iPads for their kids. They may not know the ins-and-outs of Windows but they're not unfamiliar with it either and the kids have no problems using it. Making the PC smaller wouldn't bring any new problems to the home.
Secondly Valve - is trying to create a NEW ECO SYSTEM.
It's not pushing selfbuilt SFF PCs - it's letting others do that.
Wether selfbuilt or made like the "Piston".
You think Valve has the pockets for mainstream ad-branding - with a ECO system nonetheless?
Valve will be bringing out a Steambox running linux, prehaps you should google it. And do I think they have the money for mainstream ad-branding? Certainly. Valve has a total equity of $2.5 billion.
Target audience for a Console - doesn't know or care about Steam dude.
Wake up - only geeks and hardcore gamers do.
But if they did know, then they would be interested in it.