Singing and dancing in the movies

Back when I went to see Mumma Mia, I mentioned a review that Richard Corliss had done in Time Magazine. It was very snipy of both the movie, and the idea that young people would want to go to a musical, where people suddenly start singing.

I've thought about this a few times since, and it seems to me that Mr Corliss is obviously unaware of the High School Musical phenomenon - or has chosen to ignore it. These films are aimed at tweens and up, and have been startlingly successful. And people sing and dance in them constantly. In fact the stories are basically just something to hang all the singing and dancing on, because that's the focus. The dancing is great in these movies; the singing okay (the songs themselves aren't always up to much). So does Mr Corliss' argument - young filmgoers often have to be told why the people in these movies are suddenly singing instead of speaking - hold up? I don't think so.