I think I speak for many people when I look at the Wii U it's games and realized that it looks on par or in some cases worse than the 360 and PS3. I am not willing to spend the money they are asking for something that looks the same. I am willing to spend the money on a noticeable upgrade. I think many people feel the same as much as we want to blame other factors.
We already pretty much know there's costumer confusion about what the wii u really is, with a lot of people thinking its a wii add-on. And of the 27+ launch titles only 3 were Wii U exclusive.
One was a New Super Mario Bros, the fourth installment, people are tired of the series already. Nintendoland, as great as it is, left a lot of the mainstream audience with a bad taste on their mouth after last E3 Plus its not the system seller Wii Sports was. And ZombiU got mixed reviews, which generated some bad word of mouth.
None of those are system sellers, and the rest are ports of games already available in other system, at better prices. With the exception of Assassins' Creed III.
Wii U's 2013 Q1 Seems pretty barren with only a few exclusives. The most expected known games for the Wii U between GAF people seem to be Bayonetta2/W101/Pikmin 3. Which don't have release dates ye.
If Nintendo announced some games coming in the upcoming quarters more people would feel better about the long-term investment in the console, thus they would jump in. I don't think by this point in time, people who want a Nintendo Console will want it for the hardware power, but for the Nintendo Exclusives.
And as soon as the marketing confusion settles, it will sell a bit better, as kids will see "The new nintendo toy" and will probably ask their parents for it.