Note that the result of this was a large drop in total agricultural production. It wasn't so much that people left the cities to work the fields as that the people who lived in the cities died.
Cities have never replaced themselves, by the way - urban population has always come from people leaving the countryside. When the inflow shrinks, the city will shrink even if no one leaves.
I'm sure some people in the cities died if they couldn't find a better situation for themselves, but what I had read was that many abandoned the cities because life there had become unbearable for whatever reason, generally caused by severe mismanagement by the society's rulers.
If people are leaving academic professions to work as stockers at retail stores, this does not bode well for American society long-term. You can't have an advanced economy and society without an academic class.
Counterpoint from a former tenured academic: Maybe we just have too big of an academic class.
Our universities are still trying to teach like it’s the mid 20th Century, but the economics are not in their favor. What we’re seeing is the result of them being squeezed into the new reality.
Cities have never replaced themselves, by the way - urban population has always come from people leaving the countryside. When the inflow shrinks, the city will shrink even if no one leaves.