Hmm. You say you can see it, but have we seen that to date?
Perhaps I'm assuming too much from your use of "periodic", but I don't think it's too much to expect that if it was going to happen, it would have, after nearly three decades. 20-30 years is usually considered a human generation.
For comparison to 1993's Macarena, consider Sting's "Fields of Gold", which is the most covered song released that same year, with 234 versions to date.
So, I'm not saying that old music is worse or better, I'm just saying that we forget the bad stuff, and the good stuff keeps accumulating (which goes for genres as well as individual bands or songs). Every year the new good stuff has to compete with a larger pile of old good stuff (or if you keep the pile size constant, the average quality goes up), and absent a radical change of musical tastes in the general public, that competition is just going to keep getting tougher.
Once streaming on demand broke the tastemaking power of radio (ie. the "Top 40" format), the fact that the best old music has proved to be quite popular shouldn't really be that surprising.