Then Nintendo adopts Origin, or tries creating their own thing and then we end up with another 5 years of shitty online infrastructure on a Nintendo console. Steam is probably Nintendo's best option.
No, that's not the point. This isn't about Nintendo. It doesn't matter what they do here. This is about Valve. For clarification: If Nintendo refuses, then Valve doesn't get to expand their brand that way. Sucks for both of them but that's not the point. The point is Valve doesn't get to expand Steam through an existing console maker.
And even if Nintendo turns them down, that's where the Steambox comes in. Valve can expand Steam by having it preinstalled on PCs so it is available to more people. It looks like that is what they are aiming for with that. For the umpteenth time this is not a new console or platform, its a PC with Steam preinstalled. That's all it is.
I'm not saying Valve
can't expand Steam through pre-installation and/or a Steambox. Of course, they can. It would be silly to believe otherwise. That's the very definition of expansion. I'm saying Valve can
also expand Steam by releasing their own console, especially one that could and probably would have cross platform play between PC and a Valve console, something no other console would likely offer.
You asked why Valve would
want to release their own console and the answer is quite simple: To make more money. It's the same reason every other console that has released a console in the past has released a console. If there was no money to be made, they wouldn't make consoles. Of course, there are other ways of doing things. Valve probably
shouldn't go through the headache of launching a console in an already crowded market in order to expand Steam's reach. However, it's not a question of
should Valve release a console; it's a question of
why.