It's not that simple. Farm crops are what works well for the soil and climate of that region. You don't see fields of corn in California because it's not an attractive climate for corn. Likewise, you don't see fields of broccoli in Iowa, for the same reasons.
Midwest corn mostly goes to feed for cattle, hogs, and chickens. The corn may not be really great human food, but it gets made into great human food through an extra process step.
You don't see fields of corn in California because it's not an attractive climate for corn.
Why? I've seen corn grown in California. I think the lack of corn has more to do with the ability to grow more profitable crops than corn in California.
Oh, it would grow. It's just not optimum use of the land.
Meanwhile, nothing is worth growing in the midwest unless it can handle real thunderstorms and real winter. A lot of vegetables rely on a mild climate. Our CSA farm grows a wide variety of vegetables, but they regularly lose parts of their crop to hail, late freezes, and other situations that just don't happen in California.
Midwest corn mostly goes to feed for cattle, hogs, and chickens. The corn may not be really great human food, but it gets made into great human food through an extra process step.