Let's face it, so many Wii buyers were first time console buyers, and not because they were / are kids. Wii U isn't on their radar, because they haven't actually become gamers. The committed multi-gen console gamers are primarily on PS3 and 360, and Wii U offers them nothing of note to take them away from Sony and MS.
Wii is looking like a one generation wonder, which ended up not being all that much of a wonder given Wii's going to struggle to outsell PS1 and won't come anywhere close to PS2's record, and with PS3 and Xbox 360 making late runs at Wii the final tally isn't going to look all that amazing.
Wii U really has no where to go except back to its core fan base, which is not all that big.
“The fundamental cause of the trouble is that in the modern world the stupid are cocksure while the intelligent are full of doubt.” - Bertrand Russell
"When the power of love overcomes the love of power, the world will know peace."
Jimi Hendrix
