I wonder if that's due to a (perceived) lack of interest

IMO they do need a decent high profile game to launch it with. A party minigame collection isn't going to excite anybody and while Sports Champions looks a fairly decent Wii Sports clone, the world has moved on. The sorcery game they showed at E3 would be a possible, or a SOCOM 4 bundle, or possibly the Move-enabled version of Heavy Rain. People will pay for the kit if they have a reason to want it but right now there kind of isn't one.

I can't help but be cynical about motion controllers, after having a wii for a while. However, I think Move is slightly more appealing than Kinect, which will see you pay $150 just to wave frantically at your latest red ring of death. I don't think I'll be buying into any of them.