@ShadowMarshal
Um....no offense, genuinely....but I really feel compelled to ask. Where the hell do you get your data?
Let's take a look, shall we?
Mario, on the whole, meaning ALL Mario games, by far have sold more than anything else on the planet, with over 440 million copies sold to date.
The Super Mario franchise, meaning the main platforming games, is THE biggest selling game franchise in history, with over 275 million sold.
From there it goes:
Pokemon - Over 219 million sold.
"Wii" (Sports, Fit, etc) - Over 190 million sold.
The Sims - 150 million sold.
Grand Theft Auto - 125 million sold.
Tetris - 125 million sold.
FIFA - 105 million sold.
Final Fantasy - Over 102 million sold.
And THEN Need for Speed and Call of Duty, both at roughly 100 million.
So, you're making one of two mistakes in your statement. You're either A) falsely assuming that Call of Duty is "the biggest selling gaming franchise of all time", when in fact it's not even close, OR B) you for some reason meant to insenuate that the ACTUAL biggest selling game franchise of all time, Super Mario (which tops CoD by almost 3x as much), didn't sell well on Wii U, which would STILL miss the mark, considering that NSMB U sold about 1.5 million copies on a system that has thus far sold only somewhere over 3 million units. I'd call that selling pretty damn well. So either way, I'm sorry, but you're wrong.