As far as I can see, humans have not been living in a sustainable way for 100,000+ years, and trade is part of our unsustainable pattern.
The use of cooked food helped hunter gatherers to develop better brains at the same time teeth, jaws, and digestive apparatus became smaller, starting as much as 1 million years ago. With the bigger brains, humans could develop language. They could also develop better tools. The combination of there allowed humans to win in the contest of survival with other species. Humans were able to spread their populations around the world. Trade was facilitated by language, and tokens to be used as currency were an extension of human language.
One of the ways that population of other species is kept in balance with the populations of other species is through “territoriality.” A male dog or chimpanzee with choose a large territory for his family. The chosen territory is far larger than needed, just to provide food. Without language, humans would likely have been very territorial as well. (See Craig Dilworth’s book, “Too Smart for Our Own Good.”) Humans, with their language and trade were able to find a benefit to cooperation, rather than always fighting with those from neighboring tribes, thus greatly reducing the impact of the territoriality instinct. This was one of the major ways that humans could increase their population to a much greater extent than other animals. - Gail Tverberg