Unfortunately some have found a way around that hard rule of economics via government subsidies. The corn ethanol industry being a prime example.
Farm subsidies to farmers keep food prices stable and realtively cheap.
If the price of corn per bushel dropped really low and there was silos full of it selling less than what is cost to plant and harvest , no farmers would plant it the following year and then there would be a shortage the following year(s) and the price would skyrocket.
You would have huge price swings in food and also worse yet, food shortages. One year a can of corn would be 25 cents , the next $8.00
Farmers also know by the price being stable they can purchase that new piece of equipment knowing the following years they have a market to sell their crops or at least enough profit to pay for the equipment. Farmers have enough to worry about, the weather, than worrying if the crop in their silos would sell
Our economy could not survive with food shortages or huge price swings. Talk about a hot mess, Third World style
@Bigun