In my opinion, a next gen system is NOT necesseraly a big graphic leap. It is more of what it can do that the past system COULDN'T do. I am pretty sure 7 years ago, even if microsoft or sony would of had the same idea of the wii U, it wouldn't have been possible to make a wii u consoles 7 years ago.
Predictions for LT console sales:
PS4: 120M
XB1: 70M
WiiU: 14M
3DS: 60M
Vita: 13M