"Whatever is has already been, and what will be has been before; and God will call the past to account." -Ecclesiastes 3:15
Ecclesiastes is a book replete with wisdom. In it, King Solomon examined the supposed meaninglessness of life, and also canonized many memorable pieces of wisdom, such as the famous line, "there is nothing new under the sun." This point was recently reinforced to me by another article, written over at the Art of Manliness, which essentially says that there are four main generational archetypes, and they repeat cyclically every 20 years or so. I'll include an excerpt for clarification:
"A generation reaches it apex of influence when it moves into midlife and begins to take leadership positions of power within society. Thus every 20 years as a new generation fills the midlife rung of the age ladder, and the generation that previously occupied that rung moves into less influential elderhood, the mood of the culture shifts. As each generation type is born, matures, comes to influence in the culture, and then declines and dies, it plays a role in propeling society through a cycle of growth, maturation, entropy, destruction, and then regrowth. Just as in nature, this cycle of death and rebirth is necessary to maintain the health of the ecosystem or society."