LOL. Never, ever take a GAF reaction and even try to extrapolate that to the market at large. GAF is a highly critical enthusiasts' forum with people who care about things like how the reveal presentation was structured. The general mainstream audience don't even watch such presentations, but rather watch the youtube videos of the individual games and of the hardware reveal (the Nintendo Switch reveal trailer is already north of 25 million, and probably north of 30 million when you combine all nintendo youtube accounts). GAF has been negative about the Wii as well, so you see we are not indicative of how systems will play out.
The Switch has one very important thing going for it: no one thinks it is an add-on to the Wii. Just by that distinction from the WiiU, it will do quite a bit better. I doubt they will manage to reach 40 million in less than 4 years, but more than 10 million is practically a given already.