Here's the way I look at it:
-2017 gives the Wii U a five year life cycle, like the N64 and GCN.
That is true, but you have to keep in mind that from Nintendo's perspective it makes more sense to get a new product on the market sooner than later instead of further alienating potential consumers catering to a comparatively tiny install base that third parties have all but abandoned. As it is, the Wii U is one third as successful as the N64 and half as successful as the gamecube, neither of which were considered a huge success anyway.
-Wii U was revealed at E3 2011 and released holiday 2012.
If you're looking for a precedent to hold on to consider the codename of a Nintendo console has never been revealed two years in advance of its release...
It's not like it didn't have a suitable shelf life given the success of the product. The original xbox was replaced after four years and the 360 did exponentially better.
-Between Zelda,
the 3D Mario in development, and whatever Retro's doing, Nintendo will have enough to get through 2016.
...that is assuming those projects are still intended for the Wii U... which they probably aren't. Apart from Zelda that is, though in all likelihood Nintendo is going to pull a TP with it and have a dual console release. Btw there was a more recent article about the 3D Mario game saying it had shifted development to the Wii U's successor. Also, you have to keep in mind that if they release these projects for 2016 these teams aren't going to be ready to support the NX with anything substantial until at least a couple years after its launch, which Nintendo can't risk. It makes much more sense to start with a strong launch than waste such heavy-hitters on the tail end of a failed console.
If Nintendo had those big guns to show, E3 was the time to do so, even they know that.
If they were to put the NX out at 2016, they'd have had to started development on it pretty damn early, despite their efforts to salvage the Wii U. I feel like they're only now going into damage control in the wake of Smash not doing much to bolster Wii U sales, but that's only my speculation.
Nintendo says they start working on their next consoles as soon as the current one releases, so it's not like the NX hasn't already spent several years in R&D. If it really is a hybrid console they probably started working on it at least conceptually even prior to the merging of the console and portable divisions. In the wake of their big guns not turning around the Wii U they likely shifted the aforementioned games to the NX and doubled their efforts on getting it out likely sooner than originally intended - which explains the weak E3 and the paltry selection of games for next year; Nintendo has obviously shifted their focus both in hardware and software away from the Wii U.
i cri evry tim 
