A direct outcome of such a choice will be that biodiversity dies out. If produce in America is expensive to produce, your solution will let it go extinct. Extending this train of thought, as different areas of the world become wealthy, their flora will succumb to market pressures of the type you're envisioning.

In the end, everyone will be eating foods from the least developed area today.

I'm pretty certain you wouldn't want this outcome.

(Edit1 for clarity.)