One of the more interesting points expressed is that most of the people in attendance were only just being born when the two were at the top of their game. In other words, they weren't the kids who initially bought the albums, but who came to the music later through VH1 reruns or listening to an older siblings music collection. They're nostalgic for the music of a prior generation.
I've done this myself. In 1986, at the age of 15, I grew dissatisfied with pop music and began purchasing cassettes by 60's Motown artists. After a few months of collecting the greatest hits of the Supremes, the Temptations, the Jackson 5, the Four Tops, etc, I moved on to the Beatles.
I started with their greatest hits and eventually obtained every one of their major recordings. While others in my class were listening to Bon Jovi and Whitney Houston, I was spending my spare time reading all I could about the group from Liverpool that changed the world. Though they broke up shortly before I was born, their music is so much a part of me that it really does feel as if I grew up during the 60's (when their albums were initially released).