The only one talking about next gen being their last box, the last one you need to buy, can upgrade maybe, is Microsoft. Microsoft wants to be your service provider in the living room and is not really interested in you having a dedicated games box in the bedroom. So MS is the mostly likely to quit the console race after next gen, and just focus on providing tv, movies, apps and to a lesser extent streamed games. I wouldn't put it past them if they'll make you pay for an OS upgrade 5 years into next gen.
Sony is not going to quit, their games division is profitable now and their game system is great for promoting all their other stuff, blu-ray, movies, 3D, and whatever comes next.
Nintendo will find something new for next gen. Why would they quit if they can sell at a profit from day 1 and everyone still loves all their game franchises. It would be like Disney deciding they'll bow out of making animated feature movies.







