OTOH people who don't have kids might not drift away from their single life habits the way people with kids have to once the little ones are there. They have a

OTOH people who don't have kids might not drift away from their single life habits the way people with kids have to once the little ones are there. They have a lot more time/freedom to continue going to concerts, bars, parties, etc., all of which have the potential to expose them to newer music. Even if children expose their parents to new music, it takes awhile for kids to start discovering their own music, so there's a ~13 year gap where parents are spending a significant amount of time raising kids that can't show them anything new.