When I finished reading the origin of family, when it was dealing with the primite societies living in groups, then there was no room for agresssion in that group. Everything belonged to everyone and to survive, one had to work with others.
Sure incidents like one getting angry with the other and maybe throwing few punches because they pissed the other one off.
But nothing on the scale of "I need to be aggressive to protect that which is MINE."
That kind of aggression requires thinking ahead.
Sudden outbursts are harmless.
When the reasoning is combined with the aggression, then there is potential for true malice.
You know damn well what private property is and how is its existence enforced. That is the particular kind of aggressive behaviour that I am talking about.
It also is used when coercion and force and violence is much cheaper (requires less effort) than outright direct control of the private property.
How would one person harvest a field of wheat? One person with a gun, owning slaves can have the field harvested much faster, just by claiming the private ownership of that particular piece of land.
In the environment where "My CNC milling machine is your CNC milling machine", what sense would there be for private property.
People would very quickly adapt. The doubts that you have are the exact arguments that proponents of private property use to justify it.
Useful links:
youtube.com/watch?v=4Q-bB-qywJ0
Of course baboons are dumb monkeys, so half of the males had to die off for this change to occur, but once that happened, the ratio of males to females went back to 1:1.
Humans are obviously smarter and can do such change without half of male population dying. Who would disagree? Pic very much related.
proutglobe.org/2012/10/is-human-nature-competitive-or-cooperative/