There is an insidious survivorship bias here: all that leisure time was only enjoyed by the ones who survived.
A society where the mean lifetime is 35 that works 20 hours per week gives people significantly less total leisure time than a society where the mean lifetime is 85 that works 50 hours per week.
Or in other words: all those dead infants got no leisure time at all.
A society where the mean lifetime is 35 that works 20 hours per week gives people significantly less total leisure time than a society where the mean lifetime is 85 that works 50 hours per week.
Or in other words: all those dead infants got no leisure time at all.