3DS was a bad decision by Nintendo, instead of wasting their time and effort on 3D they shoulc have focused on making a more powerful handheld and loading it up with really great games, they haven't done that, the lack of a really good 2D Mario is a clear failure by Nintendo (NSMB 2 was garbage)
Its not a lack of games, its a lack of good games that have killed the 3DS
Anyone who thinks smartphones are a danger to the 3DS just don't get it, people want good games, and Nintendo has not delivered this gen, on the 3DS and the Wii U, that is what has killed them.