> If the rich countries were to become suddenly poor, the crime and violence situation would also get worse.

I don't think it's that clearcut. There's a cultural DNA. Folks behave a certain way then when they grow up their children behave the same because that's how they saw at home. Principles and basic morals are not enforced at home etc.

I'm basically arguing that nature is less important than nurture, even if nature might indeed be worse than we think.