I'll tell you an explanation that I find commonly overrated and speculative in the extreme: the idea that things that succeed in popular culture do that because they hit the temper of the times.
Cass SunsteinIf you take anything that succeeded, just imagine it succeeding 10 years before or 10 years after, you could almost always make, with the same plausibility, the "it fit the times" argument.
Cass Sunstein