Nintendo gamers are more hardcore then we thought, that's why third party is practically non existent on the Wii. Let me explain.
For the last two generation (N64, Gamecube) Nintendo gamers have been playing nothing but the best games on them systems which consist of mostly Nintendo's first party games, since all the 3rd party games were going to the PSOne and PS2. So there just doing what they have been doing for the last two generations, they know that Nintendo's first party games are nothing but the best for them so they know they wont be disappointed. They're just hesitant to jump into the pool of 3rd party games when first party is all they've been playing for the last 15 years.
Thats my hypothesis.







