There's another reason that you don't seem to be accounting for: 50% of children born before the 20th century died before adulthood. Childhood survival rates have skyrocketed due to modern medicine, to the point where most children learn about death because of pets or old people, not their siblings dying young or mother dying in childbirth.

To be clear: I agree with the thrust of your argument and actually am a big fan of yours. I still have that epic comment about the US election you wrote 11 months ago saved. Just wanted to add another angle to the discussion