So you have something that may appeal to more traditional players, but it is in a low-end console (compared to the current generation). On top of that, the controller is driving up the price of that console quite significantly. Instead of having a low end console at half the price of its competitors, you have a low end console at 3/4ths the price of its competitors. Is it any wonder why it is a hard sell?
Except that it is still cheaper to manufacture than either the PS4 or XBox One.
Although the manufacturing contracts and specific details are not known, the estimate is that Wii U hardware is currently roughly net positive $350M. The XBox One hardware is approximately net loss of $350M, and the PS4 is approximately net loss of $750M. Sony and Microsoft are hoping losses will be recovered with software and online subscription fees to recover the losses, but Nintendo doesn't really need it since it is just extra profit.
So even though by count the two devices are tied, the Wii U is over a half billion ahead of XBox One, and a billion more than the PS4.
Again: Hardware sales are tied, but Nintendo has a BILLION dollars more in net funding from race.
When you are making a profit on every unit and your competitor is making a loss on every unit, why would you object very much when the competitor takes the lead on number of units?