My kids are grown now, 20s & early 30s, but even while they were teenagers, they listened to a broad variety, all the top-40 stuff that gets the incessant airplay and commercial push, but also plenty of old material too in a variety of definitions of 'old.' (Bob Marley was huge with the ones who were born around the time he died.) I asked my daughter once, what percentage of the music she listens to is older than she is. I would have guessed maybe 50-50. She told me, 'at least 80%.' If music is good, it will have a lasting appeal to a number of people in various situations and ages. That is how it becomes folk music.