Marketing.
It has 3D World, Pikmin 3, Wonderful 101, Sonic Lost World, NSLU, Game and Wario, Monster Hunter 3 Ultimate, Lego City Undercover, NSMBU, Nintendo Land, Zombi U, etc. That's enough games to buy a console. They really started marketing almost a year after it came out.
Price wouldn't matter because It's the least expensive, the concept isn't bad, it has good games, and PS4 and Xbox One impossible to find,