To some degree Nintendo's always going to have demographic issues when it comes to third party content, because all of the major third party content that's significant and that even "Nintendo fans" clamour for ("aw c'mon Ubi Soft don't give us this mini-game shit, we want the big franchises!") tend to be violent action games or sports games.
And this is a problem because Nintendo's family friendly/kids image and the way in which they make their hardware and market it is usually for kids-first (not kids-only, but definitely family-first/kids first).
And that alienates the audience base for these types of games, hence Nintendo has problems selling to this demographic.
Even on the Wii where they had a massive userbase, the "non-family" Nintendo titles like Metroid Prime 3, Xenoblade, Sin & Punishment, The Last Story, (and now Bayonetta 2 on the Wii U) ... none of these games really sold any better than they would have on the GameCube. Probably less actually.
How you solve this problem I'm not sure, Nintendo has problems here, hardware is definitely one huge issue, but demographics are another.
They have not had a huge hit that wasn't a family-centric franchise since GoldenEye in 1997. After the N64-era they allowed themselves to be cornered into that "kids console" stereotype more easily and backed away from a lot of the good initiatives NOA had going in the 90s.
