When was the last RPG published by Nintendo that people actually bought?
And I'm not talking about "Mario Branded" titles.
Nintendo mascot fans just don't buy RPGs. Nintendo's current fanbase is vastly comprised of mascot/Nintendo-developed games. Nintendo published RPGs are neither developed by nor contain Nintendo mascots. Therefor, they do not sell.
I'm really glad they keep trying though; they just need to build a larger base of regular gamers and titles like ASH will start selling better. Hopefully FF and DQ will help tilt the balance, but again, those are just another breed of mascot fans in their own right, aint they.