Yes, I see your point. At the same time, this comes from the assumption that the earth's resources are scarce. In reality, the earth's resources are unlimited. Therefore, there does not have to ever be a "medium of exchange," as in a Resource Based economy you ask and it is given, eliminating a medium of exchange. As of right now, we can have all that we need. Governments and the belief in "money" have put us in this situation where there needs to be a "medium of exchange."