Free markets have been free-flowing since the founding of the American colonies, to the extent that colonists refused to be bullied by elitist, landed gentry.
Economist and Historian Murray Rothbard's extensive work on the libertarian roots of the American colonies and the libertarian origins of the American Revolution all suggest that free markets do indeed make free people. The reforms that make people free and prosperous or most prevalent in market economies. The market and price systems may not be perfect, but the exceed in productive the command and control economies of Soviet Russia, and expand liberty more than social democracies which enlarge the state at the expense of individual liberty.
I do not repudiate the role of the state, provided of course that the state provides the means for trade, then gets out of the way, as well as provides recourse for enforcing contracts and prosecuting fraud.
I believe that progressive reforms dismiss Austrian economics, and free market advocates, as mere "theory" because the means of trade, pricing, and movement of goods exceeds the limit of the human mind to plan. As one liberal economist remarked, "You can't make a pencil." The planning that would be required to ensure that raw materials, distribution, assembly, packing, and sale would take place in an orderly and timely manner would exceed the capacity of even the most keen and foreseeing intellect.
Market forces that drive trade cannot be held, but neither can the forces that made language possible, that explains meteorological phenomena, or that accounts for the development of other cultural institutions, like family, law, and even intellectual inquiry.
Free market development is not a theory, in that trade takes place all over the world all the time. I cannot see the wind, but I know that it exists because the leaves on trees move and waves swell and crest on the ocean. I do not see radio waves bouncing around the earth, but I know that they exist because radios work when placed properly to pick up signals. In the same manner as wind and radio waves, I do not see market forces, I cannot understand based on my own limited intellect the persuasion and ministration of the free market, but I see the effects of it every day: in stores, in theaters, anywhere where something is bought or sold.
Free Market, or Austrian, economics are not "theories", for these explanations of economic forces prove themselves every day, although the elements that compose these forces cannot be caught or dissected or planned. This fact may war against the progressive of socialist -- and certainly the Communist -- frame of mind, but planned economies, force compelling "fair exchange", creates more problems than allowing the "Invisible Hand" of the marketplace to work, unencumbered.