There's one good way to look at this--we're going to be arguing about music from the 1960s and '70s for another thirty years or so. Can you imagine someone in 1970 having anything remotely resembling a conversation about music from the turn of the century? Can you imagine any other era in American history where the popular music of one decade remained relevant for sixty or seventy years?
And I'm not talking about a handful of incredible artists. I'm talking about at least several thousand albums and several hundred different, distinct artists who still sell relatively large numbers of records.
Popular music was something consume and move on from. We have not moved on from an era running roughly from 1964 to 1979. Incredible.