Gee, I only spent a couple of years trading commodities. I should have talked to you first, huh?
The market has rules just like any market. You decide to leave, then yes, the producers can charge whatever they want. It's the market that stabilizes prices. It may not work in our favor all the time, but it sure beats the hell out of the alternative. If you don't like it, I have bad news for you, most everything you buy is in the market. All of our food is in the market: cattle, wheat, rice, soybeans. Our currency is actually in the market. Our cotton and lumber are in the market. It's all market controlled and they do so for a good reason.
So isolating America is no answer because then you would actually have what you claim the commodities market does, and that is companies maximizing profits which means we all would get screwed, especially when something interferes with the production of products such as droughts, floods, hurricanes that knock out oil oil platforms, forest fires and so on. Prices will still go up, but not by nearly as much if we only relied on ourselves. Think of it as spreading the misery around the world instead of suffering the misery exclusively ourselves.