Interesting that you mention the Enlightenment. The Enlightenment started with the depopulation of Black Death, the Great Famine, and the subsequent 3 centuries of warfare (Hundred Years War, War of the Roses, Wars of Religion, etc). Europe lost roughly 60% of its population. As a result, the survivors could bargain for higher wages, which led to a power shift from the entrenched landed aristocracy to the newly emerging merchant and guild classes. (Cynically, once the lords could no longer use peasant labor to quell any challenges to their power, they lost that power to a more egalitarian middle class.) Additionally, the survivors were overwhelmingly former members of the aristocracy - the new merchant classes were largely made up of the younger sons of noble families who previously would've been shut out of an inheritance by primogeniture. They were often educated the same way as their older brothers, but lacked control over resources in the feudal system. As the feudal system collapsed, they spread the values of the nobility into the rest of society. We got egalitarian values because everybody's ancestor used to be a lord, and most of the peasants died off.

There are some pretty obvious parallels to the current situation. It's very common for pandemics to lead to the collapse of current political organization.