Currently, meat serves the important function of regulating the supply of cereals. When there is overproduction, the grain producers can still sell for meat producers, not going out of business. Where the production reduces, meat producers sell thiner (and sometimes younger) animals, freeing more grains for human consumption.

Left alone, grain consumption is extremely inelastic, and production is extremely variable - not a good combination. But yes, it's not that hard to create other mechanisms for regulating that market, even world wide.