I think he's low balling the Wii U but he's not *that* far off either. My guess would be about 30 million or slightly less than that.
The GameCube sold about 460k in November 2002 (it's second holiday season), I think the Wii U is probably in tough to match that even with Mario 3D World.
Mario/Zelda/Smash etc. only really get you 25 million-ish consumers, the Wii was successful because Wii Sports and motion gaming brought in many new gamers. People like Mario sure, plenty more than 25 million, the issue is when you start to ask people to buy an entirely seperate console just to get those Nintendo games, for a lot of people that becomes a pass.
Even with something like Super Mario 64, lets not forget, the majority of gamers that gen were content not owning a N64 at all and going with Playstation and maybe having something like Crash Bandicoot instead because the Playstation was a more wide appealling console especially to game enthusiasts.
A lot of people like Nintendo but they're not *married* to Nintendo the way Nintendo fanatics are, you really need to give them a compelling reason outside of the just the same Nintendo staple franchises to buy a Nintendo console, because they're pretty much already going to get a PS4 or XB1 already to get the wider variety of games that they want (simply put Nintendo is only one developer, a lot of the third party community is absent on Nintendo platforms).
