OUYA
Seriously though, right now I don't see anyone really leaving. Nintendo leaving would mean the end of Nintendo, and I doubt they would go out without a very long fight. Even if they went third party, it would still be the end of Nintendo as we know it, and I think it would have a terrible effect on their games output.
Microsoft would suffer the least if they chose to do so, but I still don't see them really exiting, but rather rethinking their gaming strategy. They would be missed.
Sony, well, it all depends on Sony corp. Going along as they're doing now, their gaming division looks very very stable.








