I generally manage to blight the urine extractors by pointing out that trad music is *classical* popular music - so popular that it's still remembered and sung long past the time and far from the place it originated.

That sometimes stops the brighter ones in their tracks while they work it out, and then we might have a discussion about what, if any, popular music from recent memory will similarly pass into the tradition and still be loved and sung a hundred years from now (if, of course, there's anyone left to sing it, a hundred years from now).