How can Wii sustain its leading position in Japan?

[othman]

We are working on project for business strategy. The project is about Wii strategy in japan. I'm not a console game fan, although I play winning eleven on PS3 with some friends,  and some games on Wii with my wife :).

I need your help for good sources and discussing the following questions:

Accourding to this website and other, Wii is leading by far.

How can Wii sustain its leading position in "Japan"?

what  are Wii users  demographics for in "Japan"?

thanks you