This has been an ongoing problem ever since the N64 era and its been debated up to high heaven. Pretty much, third parties have come to expect that they cannot make a profit on a Nintendo system, for a multitude of reasons. From 'experience' to coming to find better profits on other systems (mostly Sony systems) to simply having this illusion that Nintendo doesn't cater to the 'hardcore'.
In the end however, this generation, Nintendo is on top, so third parties are being put on the spot. And time and again, they have shown resistance to wanting to work on a Nintendo system. And not just in this generation, but all the way going back to the N64 generation and into the GameCube generation. Its pretty evident that third parties and Nintendo have reached an impasse, either over the lack of graphics or fighting over 'ideals of gaming'. And there's little that's going to change the situation. Even with some third parties losing money hand over fist by choosing to ignore the Wii.
Which is sad, since some of those companies made some of their best money this gen with the Wii initially. It makes no financial sense.
And what makes even less sense is how companies seem so focused on graphics this gen, yet last gen, the PS2 was on top when it had the 'worst' graphics. Yeah...either the 'industry' is full of a bunch of companies that are all twisted around and really trying to ruin themselves...or very hypocritical.
Six upcoming games you should look into:
Essay Pro