The Great Depression was not a sign of the failure of monetary policy or a result of the failure of the market system as was widely interpreted. It was instead a consequence of a very serious government failure, in particular a failure in the monetary authorities to do what they'd initially been set up to do.
The lesson about food is that the most predictable and the most orderly outcomes are always not the best. They are just easier to describe. Fads are orderly. Food carts and fires aren't. Feeding the world could be a delicious mess, full of diverse flavors and sometimes good old-fashioned smoke.