Only a poor student of history could fail to notice history's cycles. The future can't be fortold in detail, but asking the question "Where are the cycles taking us?" gives you a better chance of guessing general shapes than anything else I know.
So it's easy for a student of history to look out at the United States and guess that we're approaching a libertine peak, and that over the next couple of decades we should expect to see the pendulum swing away from the wild excesses of the Baby Boomers back in a more "conservative" direction.
But at my age, I've never lived through a shift. So had I guessed how the counter-libertine shift would occur last week, I would have guessed a gradual cultural waning of the libertines and a gradual cultural waxing of those of a more conservative bent, with the advocates not changing their own views but their relative influence changing over time.