As an American born and raised in Illinois I can also inform the rest of the populace our corn also gets used to make ethanol, an alternative fuel source.
Im guessing they also never seen how much the coffee from there cost. Plus supply and demand you dumb fucks. The cost will skyrocket. Kona coffee ranges from $30 to $100 a bag. Think of a massive increase of demand. Are we going to pay $100 a bag for low end stuff?
Hawaii does have the largest coffee growing industry in the entire US but they are severely limited by the amount of available land. Compared to other coffee-producing nations, the Big Island is microscopically tiny, so they mainly focus on high quality, artisanal product sold at extremely high prices. Not that I would mind if all the coffee sold everywhere would be replaced by Kona coffee overnight, but it just isn't feasible.