One very well establish law of economics is the law of supply and demand. If there is a demand, there will be a supply. If supply exceeds demand, prices will fall. If demand exceeds supply, prices will rise.

Markets are generally efficient in allocating resources and maximizing 'the size of the pie', especially under fantasy conditions (perfect information/competition), but when things get bad enough the supply may have no interest in observing the social conventions (property rights for example) that make the system possible. Unlike the market for most goods, the supply of labor consists of agents capable of starving, dying, stealing, waging war, etc. Thus market forces themselves can result in economic collapse and gross inefficiencies.