Most music I've listened to, I've tended to love for a few years or so, and then kinda moved on. I still love stuff like Floyd, Zeppelin and Sabbath, etc, but it's been years since I actually listened to any of those albums.
I was thinking about the music I was listening to back in 1992, when I first heard DT. At the time I was really in to Guns n Roses, Metallica, Queensryche, Nirvana, Pearl Jam, Soundgarden, Janes Addiction, Red Hot Chilli Peppers, REM, Throwing Muses, the Pixies - none of which I actually listen to that much these days.
So I don't think it's unusual to stop listening to music, your tastes change as you get older. I find it unusual that I'm still listening to DT some 22 years later. There have been times when I haven't listened to them that much, but I've always come back to them sooner or later. They've provided me with something fresh and different with every album, and kept my interest alive.