https://www.sciencedirect.com/science/article/pii/S109051381...
The Black Death is pretty well accepted as a contributor to the end of feudalism. I guess you’re positing that somehow that would be the result of survivors feeling elated at having gotten past the catastrophe (which is a temporary emotion), versus their facing an easier life as a result of 50% of the population dying (an effect which lasts a lifetime). Seems implausible to me.
But also, that the reduction in labor supply lead to vastly improved outcomes for laborers is pretty well attested. Lords of the manor started competing for labor because it was scarce. As a result, laborers were able to transition into owning their own property. It was a big deal. And it has to do with permanently reducing the population to well below the Malthusian limit (the plague periodically re-occurred for centuries, culling the population each time).
Is this entirely a genetic thing or are there also cultural components? I’ve long entertained a crackpot theory that North America will be almost entirely Mormon or Roman Catholic in 200 years, partially for this reason. The only reservation being that secular-humanist culture seems to convert people from more traditional cultures even faster than they reproduce....
Or Muslim, although that's more likely in Europe at this point.
> The only reservation being that secular-humanist culture seems to convert people from more traditional cultures even faster than they reproduce....
Perhaps in a few hundred years secular humanism will be seen a memetic Black Death.
As for the Black Death, the personal and societal restrictions that result from not wanting to die from casual contact were probably quite a relief to escape and reverse. I don't know enough about history, but I could imagine that kicking off a positive chain reaction. After a cold season, people love to play in the sun.
This part is just speculation on my part, though; you're welcome to continue siding with Thanos.