While this is a thought provoking article, it makes assumptions that are not necessarily true. If a person thinks in terms of resources and not in terms of products you can begin to see the fallacies. It is easy for a group with common interests to share resources. The problems begin to arise when the group doesn't have a resource that it needs. As an example, if the Iroquois lived in a region where there was no obsidian which they would want for making tools and hunting instruments, they would need to approach a neighboring community that has access to the material If that community didn't want the Iroquois to have that material because it would upset the balance of power in that this material could also be used for making weapons of war. If the other community already had all the resources it needed to comfortably survive, how would the Iroquois over come their reluctance to give them obsidian? For the Iroquois this is becoming a matter of survival of their people. It they don't have this resource they won't have the tools they need to farm or to hunt. This is just a simple example, with more complex societies the more complex the problems. In my life time, I have seen people try to sustain "gift economies". I remember the communes of the sixties. On paper they sounded quite reasonable. Most of them didn't survive or evolved into capitalistic economies. One last point. Slavery was not an out come of the invention of money. It was the out come of the invention of war. What do you do with enemy combatants that surrender? Do you just kill them? Not if your humane. You make them slaves.