What constitutes nonmarket forces is mostly a matter of opinion. Unions? Monopoly power? Government enforcing contracts? Government competing in the market? Na

What constitutes nonmarket forces is mostly a matter of opinion. Unions? Monopoly power? Government enforcing contracts? Government competing in the market? Natural disasters? Normal weather? Taxation? No taxation? Strong property rights? No property rights? A "perfectly free market" is a meaningless phrase dressed up to sound like "frictionless in a vacuum". It exists for the purposes of cynical lobbying.