Pop Culture

Working in a restaurant, I hear pop music all day long and hardly ever end up turning my car radio any more. So when I do, I expect not to hear anything I know (because the pop music at work is between 6 months and a year old), and I am always surprised to realize that I still know a good majority of what is on. Does this mean that pop culture isn't all that relevant or that time just seems to move a little faster than we expect it to?