The hardware isn't sold, it's leased, but the effect is the same: we manage the onsite hardware, fix it when it breaks (next day replacement), and send out new hardware every few years. The hardware is literally plug and play, and works correctly behind a NAT router with DHCP.
We actually decide what hardware a customer gets (it's based on load -- standard provisioning stuff), although customers can upgrade to a system they don't actually need for a fee.
I think this approach is way better for customers, and the response so far has been extremely positive. No longer do they have to worry about provisioning and maintaining hardware, or even deciding what to buy. Of course they don't know the best way to provision hardware for our software. Why would they?
It'd be really interesting to see this approach done in the consumer space.
This being said I am not sure this is really going to be necessary because there has not been much of race for graphics in game recently on PC - I still have a GPU from 2 years ago and it still runs all games very well, even the latest ones. This may change with the introduction of new consoles, but I am not too sure about that yet.
All custom specs will be handled like they are now, expect now there is a single target spec everyone agrees on.
Given how aggressively they've pushed to make their games work on Mac and Linux (going against the grain of the industry), and given the years of massive user configuration surveys, and the fact that they've essentially run a fractured ecosystem for years, I'd bet they have something up their sleeve here... or they have a reason why this isn't as big a problem as it's been in the past.
Essentially, how often will Valve upgrade its Steam Box? Certainly more than every 6-7 years. For those of you thinking right now: "you can ugprade it yourself!", well, yes you could , but that defeats the whole purpose of having one standardized spec for developers to target. Throw in a new graphics card here and there, and you've suddenly splintered your user base into those with PCs, Official Steam Boxes from Valve, and Official Steam Boxes from Valve that have been upgrade by the users. And now, certain games will only work on some combination of those three.
I'm a fan of Valve, their games, and their culture, and want to see this succeed. I'm sure they've put much thought into scenarios like this and trust them to make the right decision.