Well the other problem with the Wii U was Nintendo foolishly made their system too close in horsepower to the 7 year old XBox 360 and six year old PS3 which everyone already owned.
So there was no incentive to purchase a Wii U third party game over the PS3/360 version.
If there was a large leap in hardware that allowed for considerably better graphics, I'm sure more people would've bought some of the Wii U third party games, but Nintendo instead bet the farm on a silly gimmick controller that is very difficult to integrate into most games in any compelling way (look away from the main screen so you can see your .... map! Amazing).