Nintendo's fate as a home console provider was basically doomed the moment they decided that this:
Was an acceptable look for a home console and decided that on top of that they would give Sony 18 months to build a headsart with the Playstation 2. You may as well have just put a Fisher Price logo on the system and called it "Babyz First Game System". I didn't mind the design personally, but for the market and where it was going, that design was a disaster.
That was basically the acceleration of the end of Nintendo as a relevant long term home console force (N64 would be the beginning of the end).
Wii U was just the death knell.