The Wii will do fine for a long while. Like past Nintendo creations, it has a lot of casual gaming games. I personally like it more than a XBOX 360 or PS3. And plus, I believe the cost for a Wii has dropped some. Has the PS3 dropped any? I don't really think so. I think it's still at 500$.
I doubt parents will shell out 550$+ just so their kid can play one game. Unless they're spoiled rotten.