“Aging” is a bit misleading here - it’s about the society’s age, not the people in it. I wonder if there is some selection bias. Many potential “civilisations”

“Aging” is a bit misleading here - it’s about the society’s age, not the people in it. I wonder if there is some selection bias. Many potential “civilisations” might not appear in the historical record, if they die too young. That could explain the lower risk of death for the first 200 years.