I think it's more an indication of higher expectations in child-rearing. If you're struggling daily for survival and 7/10 of your children will die before age 6 I don't think can afford to spend hours every day experimenting which method will get your child to fall asleep without crying.
Except children in traditional societies demonstrably cry less and are happier (both parents and children). Anybody who has spent time living in traditional societies vs living in the West see the differences - chiefly, the sheer anxiety that western children are introduced to from the first day they step foot in the world.
Doesn't surprise me that people in a society that values individual liberty develop more anxiety as they are expected to take responsibility for their own decisions,
as opposed to a society where traditional authority commands you exactly what to do and you'll obey or else.
