How many people do you need to have a successful division of labor if they trade among themselves? In 19 hunr 19 hundred, forty % of americans were farmers. If all we coud do was trade among ourselves, just those 80 million, how my how many people we nee to devote to certain tasks? Farming being one. A non current level of technology. We'd have a much lower level to start with. It would take a long, long time, i think, to get back to anything like a modern standrd of livingimean,. Am, ah, like inprincible. I think you could ave aself.