It's not that Deep Purple made a comeback... the band has been to Argentina almost twice per year in the last 3 o 4 years... they never left, but they never released new material either.
I think the music industry is not that poor, but is changing. Media has transformed the industry, and so did internet, itunes and the mp3 format. Everyone with a blog or a space can develop a music career. And everyone with an internet connection gets to listen any kind of music from any part of the globe. In times like these, where young people can listen to old music, it's reasonable for old bands to come and play for their new fans.
PS: I've been to the Velvet Revolver show last year and it rocked!!! The crowd went crazy and so did I, even though I didn't like the band in the first place
