I have a wii, and I've never felt like the games cost more than any other system. My brother's had different systems for as long as I can remember (he's 27, and I'm 24), and I can't ever remember games being cheap. He's had playstations, sega systems, super nintendo, all sorts of different ones, and they've all been around the same. Obviously, the older systems would drop the prices when newer ones came out, but that's about it.
Really, considering the amazing things that you can do with a wii, I don't feel like $60 is that much for a game, especially this game. I play mine all the time, so is $60 worth huge amounts of fun, a new appreciation for the beatles music, and learning that my four year old loves them as much as I do? Absolutely.