This is an interesting topic. Interesting enought that I feel compelled to pull some completely ungrounded theorizing out of my tuchis.
I think what drives these cycles at it's root is that people are like ducks -- they form their deepest emotional attachment to the music they hear when they're young. This applies to people who actually make music every bit as much as it does to punters. So when it comes their turn to provide the soundtrack for the zeitgeist, they turn naturally to the music of their youth. They update it with influences of everything that has happened in the meantime, changes in music technology, etc. And this trolling through the wonder years is also reactionary -- they use elements of what they liked about music past to counter what they dislike about music present. So if House music is the current vogue, it's soul and gospel roots are an antidote to the blandness of minimal techno, combined with nostalgia for the raw sounds of early House music. This will be replaced in due time with something else again. And not so much amongst us out in flyover country, but in New York, London, Berlin, Paris, Barcelona, there's the element of fashion involved. Once something becomes too popular amongs the hoi polloi, the in crowd needs to find something different. Here's hoping that there's no big resurgence of Happy Hardcore, which by the generational clock, is due for a revival....
