Ultimately, they will also be driven out of business. But the land, labor, and other resources once used to grow food in China will be used to make clothing for export to America. And all the resources once employed to make clothing in the U.S. will now be available to make food for shipment to China. In other words, as a result of international trade, the two countries will tend to specialize their production. In this story, the U.S. eventually produces only food and no clothing.
China produces only clothing and no food.
Before trade, if America wanted another unit of clothing, then it would have to sacrifice two units of food production to get it. Now because of trade with China, the U.S. need only give up 1.11 units of food. That's a substantial savings. China also appears better off because they have cut their cost of obtaining additional food from 1.67 clothing units to 0.90. It looks like a win-win situation.