No it’s not a good comparison. The bulk food prices themselves are indeed sold on a similar commodity market, but the pricing of packaged goods is marked by companies selling those packaged goods. Oil and gas are sold at the rates bought and sold through futures contracts directly from the producers. You’re paying the rate the traders got it for, usually with a regulated mark up. If you’re buying from a private utility then you’re on your own buddy.
That usually happens when people don’t want what you’re selling.