This is slowly becoming a worrying trend... 3DS (outside Japan), Vita and Wii U are all doing terrible. And let's not kid ourselves: The other next generation consoles are not going to fly off the shelves at a $400 price point either - they might do 10m each in their first full year but it won't be Wii-like sales (or even PS2 sales probably).
Just to be clear what these numbers mean: The Wii U is selling slower than the Gamecube did. It is currently headed for 20m lifetime sales and it is selling way slower than either the 360 or the PS3 did at first (like 1/2 of the PS360's numbers in their first year). The Wii U is close to being dead in the water. It is selling closer to Dreamcast numbers than sales of most "big" consoles. But unlike the Gamecube the Wii U is sold at a loss - they are not going to turn a profit on the console at this sales pace: Slower sales mean higher production costs per unit and lower software sales - basically their loss per unit increases over what they expected. Software development costs are fixed costs, they won't go down. Mario Kart U will be, say, $5m to develop no matter if the game sells 5 million units or 20 million units --> the net profit decreases. And it also means third parties won't find a healthy environment on the Wii U so they'll stay away from developing for it - which will result in less royalties paid to Nintendo. It's a vicious cycle.
And the Vita is selling even worse. 28k worldwide is close to non-existent.
(Not meant to provoke flamebait, btw. But I was really harsh on the Vita and I'll be equally harsh on the Wii U. These are not "normal" or "slightly lower than expected" sales for either console.)
