1 fish never come to you by themselves. one can not eat as much fish as he or she want to. Furthermore, in certain condition everything has scarcity.
2 i cannot see your point
3 your assumption is ridiculous. In that time, do you think there was so called economics? People didn't even trade with each other. all the properties are co-owned by all the people in the tribe. And in households, parents never trade with their children, but they have to compete with other household so they can get enough food.do you think so? there is even no market.