It is excellent dance music, which has to be a big part of it. But I also think it's endured because it's not generation gap music - it's been around for over a generation, and teenagers love it as much as their parents. Adults don't see it as greasy kids' stuff and kids don't see it as museum music for the oldsters; it's what all those lefty folk revivalists were looking for when they went in search of "peoples' music," except they never thought to look for dance music in the city.