This generation things are odd, and not following any historical trend.
While the Wii has the largest install base, and the largest amount of shovel ware....which are 2 indicators of the successful leading console, it simply doesn't have all AAA 3rd party games which historical speaking it should, in fact what's actually happening is that the high majority of AAA 3rd party games are actually appearing only on the PS3/360 and PC.