RolStoppable said:
You must have missed all the ports the GameCube received during its first three years on the market. Third parties didn't take the stance that they did not want to work with Nintendo at all. While Nintendo didn't get many exclusives, they could at least bank on competent ports of multiplatform games for a while. The HD twins combined only ended up with greater marketshare than the Wii, because third parties kept pushing for it. |
I know, and that's true. It still doesn't answer the question, why the different approach to partnerships for the Wii, when the cube got them. The philosophy must have been different, it seems to be the best answer we honestly have.
For the HD twins, here is a worldwide graph of the curves between them and the Wii, for discussion:

But since this seems to be a more American phenomenon I provided the US version:








