I think "it's human nature" is an excuse made by the ruling class to quell challenges to the system that benefits them.

Sociopathic hoarding and anti-social manipulation is an abberation that our system artificially elevates and rewards.

If we were culturally more hostile to attempts to rent out our lives and natural resources back to us, and didn't put zero-empathy profit hoarders on the front of magazines, things could be better.

I agree with you on group sizes though. When people are treated like hyper-specialized insects with ID numbers instead of identities, funneled into highly-specialized roles, every one a stranger to the other, something has gone horribly wrong.