So it's all the fault of the evil Third parties.
But lets look at it from Nintendo's point of view.
Does the lack of 3rd party support affect the console sales ? I would say not a lot.
What positive effect does the lack of 3rd party support have ? My Nintendo 1st party are selling like hot cakes....
Would more third party support affect my business ? Most likely a little. better third party would eat into the sholveware sales, as Nintendo I am indifferent to this, I get the same royalty fee on either. But it would probably have a slight impact on my first party sales ( provided we consider than the overall software sales on Wii woudn't increase a tonn , just that the spread of the sales would be different..).