You don't seem to understand that Android already is first. This is a $100 Android box with an 'app store of its very own!' and not much beyond that. We've already got Android and it's not difficult to make a similar enclosure. We've already got better hardware! The cost of porting from Ouya to other Android consoles in general is almost assuredly trivial to possibly zero depending how lazy they are about their software stack (i.e. no real reason to deviate from typical Android practices). All they have to differentiate themselves with is what they've added to Android and so far it looks like 'not much'. There's no reason for exclusivity on Ouya.
No, it's not a $100 Android box - it's a 100$ Android console. And I don't know any other Android system specifically designed for that so far. You don't keep your mobile phone or tablet plugged in to your TV and neither do you plug in a game controller into either of them usually. Also generally tablets do not mainly care about improving performance specifically for games, which mean given the choice of faster 3D or improving other hardware parts a typical tablet will not go for 3D. And yes - easy porting games to/from other Android systems is one the big selling points. If you think a computer is a computer then there is pretty much no point for ever buying a game console, nearly everyone has a more powerful PC in the house already.