That perspective is often misunderstood as asserting that an economic system is value-free--sort of a moral relativity. But that's not the conclusion I come to looking at it that way. Rather, because economic systems are malleable, and different system parameters produce different outcomes, we have a responsibility to set the parameters to produce an outcome that expresses our values.

When I hypothesize about post-free-market-capitalism economic systems, you might've noticed that I'm striving for a system that expresses the same values and does so even more effectively. For example, I take a dim view of concentrations of wealth because they undermine the values of equal opportunity and mobility, as well as increasing the risk of coercion of the individual. FMC possesses the properties of eqalitarianism and a degree of individual liberty, but I think that it can be improved upon. Not by removing its moral aspects, but by building a system that better supports and reinforces our moral values.

An economic system handed down by God or imagined to be a consequence of the laws of nature posseses no moral properties; it just is. But when we realize we have the power to create economic systems, we assume a moral responsibility for the consequences. That's why I don't feel that I'm treading on sacred ground when I contemplate tinkering with FMC; I feel like I have an obligation to think about improving it.

Your final paragraph summarizes the history of economic thought so far, but it hardly makes the case that free-market-capitalism can't be improved upon. Surely you don't want to be in the same boat as the Patent Commissioner who wanted to close the Patent Office a century ago because everything had been invented?