Why has Japanese 3rd party support almost completely ceased for the Wii?

[BoneArk]

I've bought 2 games for my Wii so far this year and they're both made by Japanese devs. No More Heroes 2(Grasshopper Manufacture, Ubisoft just published the game in North America)and Tatsunoko vs. Capcom(Eighting/Capcom). I also have Capcom's Monster Hunter 3 Tri pre-ordered. Maybe at E3 we might see more.