you would expect the young to outnumber the old

Kinda depends on how you define the two cohorts.

We’re also overlooking a seminal moment in history where

• Vaccinations
• Nitrogen rich fertilizer
• Fossil fuels
• A sixty year long people of relative global peace

All came online at about the same time, radically improving human life expectancy over two generations.

As a point of comparison, the county of Tibet had an average life expectancy of 35 in the 1920s and 72 in the 2020s.