I don't know. I think the huge market share that chemical and processed food holds really skews the market. I'm pretty sure there would be a huge change in prices if there was only local food, and more expensive exotic food.
But to be honest.... it is only speculation since we will never see a 100% overhaul unless there is a nuclear holocaust or some other really HUGE infrastructure changing event.
I guess if the only supply were small scale sustainable organic foods, the prices would change. But I’m not sure in which direction.