That's charmingly understated. I have a few guesses about what causes the 'rhythm' (or cycle) of politics and I wonder if they have analogy in punctuated equilibrium theory: the cycle of buy off, wherein the initial strong push is met by both repression and cooptation--the first exhausting people after a time and the second appeasing and incorporating large sympathetic portions of the movement; that lessons learned by one generation are not entirely grasped by the next, due to lack of direct experience; the tendency of ideas spread to spread wide and not deep, which may lead to large initial leaps followed by backtracking when the territory won cannot be held; that those who innovate pay a price for the energy put into innovation while the beneficiaries benefit without the cost (free rider) sidelining the innovators. All these happened in U.S. Women's Liberation, I'm sure there are others.
Jenny Brown