Not selling somebody your tomatoes primarily affects your tomato growers who will go bust, not those buying the tomatoes - particularly if they have plenty of tomatoes internally, can easily produce them or can get them from those lovely tomato growers in China in return for oil and gas.

There's rather too much faith in the power of the mighty US dollar. Quite a few people are going to find out the hard way that electronic impulses on a computer don't mean as much in reality as gas and oil supplies.