The console is just the ante into the game, same as Xbox,PlayStation,Nintendo. Having a standard would allow hardware manufacturers as well as game devs to come into sync.
Establish a clear casual,mid level, hardcore specs every couple years and the software will be able to anticipate what it will be running on when it's released. Now GPU,CPU and SoC manufacturers will be confident that if they release hardware that conforms to each spec they certify their hardware will run at a given level. Now ARM licensees will be able to make sure the right components are integrated and they progress in the direction the consumers want/need.
Valve is more of a publisher than a hardware manufacturer anyway, they will likely be much happier just sitting back and offering OS images than make a gripe about who gets to make the physical box.
I personally would be excited about a variety of boxes. The companies that are currently on the cusp of ARM components that already have the grunt to play casual to mid level gaming and without need for a battery/display/fancy case they can do it for much cheaper. Go to your local big box store and pick up a mid level gaming system with WIFI/HTPC capabilities plus abilities to connect to a wide selection of cloud services and your good to go.
If we could get Valve to make a mechanism that would allow the resale/trading of games I honestly believe the market would soar. If there was a Valve sponsored "swap meet area" it would allow for people to become much more involved and if any money was actually made it would likely be dumped right back at the Seam Store. I guess that is a discussion for another day but ya a standard would not be a bad thing.
Hardware makers don't like sync or standards. They like platform lock in and exclusivity to motivate buyers into buying their product over a competitors, or buying both. Honestly, the steam box will end up being an x86 processor of some description with some ddr3 memory and a discrete gpu of some kind, designed to run games well at 1080p, and they will probably use some kind of boot-to-steam system (I mean steam has its own web browser and everything already!) where they replace the usual DE with just big picture Steam.
