That is a very rudimentary understanding of the system that doesn’t always pan out in a particular time frame or due to external factors.
It takes time for that effect to occur
It doesn’t take into account barriers to entry, of which there are many for food
It doesn’t take into account that there are are actually a small number of companies that own the bulk of our food supply chain and it’s in their financial interest to keep prices high for things that are perceived as luxury