To the Moon!
On a serious note, Nintendo will be fine. The Wii made Nintendo millions so they can survive a "failure" this gen even more than one gen and considering how well the 3DS is selling they aren't going anywhere. Like Salnax said, worst case scenario, the Wii U sells like the GC, but they will still make profit out of it (maybe not in the first year).
Nintendo can take a 20 billion yen loss ($257 million) every year until 2052, they aren't going anywhere anytime soon.
Nintendo and PC gamer








