As much of a success Mario Kart 7 was for the Nintendo 3DS  it’s actually quite surprising that the game was never ported for the Wii-U back in 2011.  Since its release Mario Kart 7 had managed to sell over 15 million units worldwide on the Nintendo 3DS and is arguably the best racing console for that handheld device.  If Mario Kart 7 was released for the Nintendo Wii-U back in the early 10’s the game could have possibly have sold more units worldwide than it did on the 3DS.  But then again since the Wii-U was a commercial failure and sold less than 20 million units worldwide since its release having it on the Nintendo 3DS was probably a better idea in the long run.