Realistically, the Wii U, PS4 and "XBox 720" are the only consoles that really matter ...
The Steam Box will likely sell poorly compared to the mainstream consoles but will (probably) establish a niche market. For PC developers it will be worth supporting because it simply means making sure your game plays well with a gamepad which they (mostly) already do to support other consoles.
The other systems will do what every other small company does when they enter the console market, they will crash without ever making a dent.







