In general, “the rich” mostly includes people who are intimately familiar with the Law of Supply and Demand, and who are able to use it in widely different business enterprises. In general, most such business enterprises involve hiring workers and selling goods. The general population is the source of both the workers and the Demand for goods. When population increases, so does competition for jobs (wages may go down) and goods (prices may go up). The rich can profit from both aspects of the situation, so long as they can forestall increases in productivity of goods (which process often includes making more jobs available; both types of competition are reduced). But almost no one else can profit in that situation.