The idea of free markets being the way to increase the Wealth of Nations, and thus the wealth of its citizens, was crystallized by Adam Smith. He rationalized that if the producers of goods and services were allowed to pursue their rational self-interest, constrained only by common sense rules preventing one producer from getting an unfair advantage over other producers, the consumers, citizens, would get the best products at the lowest price.
The citizens would also benefit by the producer freely competing for the labor that would be needed to produce the goods and services that would be in demand my the marketplace.
The problem is we no longer have free markets. Our markets are controlled by a small group of entities. What type of control do you favor?