Sony's already said this console cycle will likely be shorter than the last one, so by 2017/18, we will probably start to be hearing about the PS5.
One of Nintendo's problems IMO is they follow the stupid same release pattern as Sony/MS do. If you want to be different, one really easy way to do it (instead of trying to come up with some kind of controller gimmick every time) is to simply discard that cycle entirely.
Launch 2 years ahead of your competition and release a machine that's sufficently more powerful than what's on the market at that time and you should be able to build up a nice sized userbase before the other two have to start over at 0 again.
Even the Wii U, as much of a disaster as its been, had it launched in fall 2011, you're probably looking at an install base well north of 10 million by now. Had they ditched the tablet pad/chasing the "Wii formula" again and simply made something say 3x more powerful than an XBox 360 ... they'd probably be clear of 15 million right now easily and on pace to hit 20 million soon after this holiday season.
It would take Sony and MS years to catch up.
