I think this idealization of “hunter gatherer” society is absolutely insane. It’s like arguing the moon is made of cheese. People were likely not happy being hungry, scared, and afraid most of fucking the time.
For all we know when people start to travel cross continent in minutes, press a button and have instant steak printed, we cannot assume they will be happier than everyone alive today. They will have their own set of issues to weight them down. If nothing, boredom.
A person that had 'happiness' and now is in a less secure position.
A person surrounded by happy people, but doesn't feel that way themselves.
Relative privation does weird things to people.