This is a statement about possibilities, not about what will actually happen. In the real world, there is not central authority deciding which country should produce roses and which should produce computers. Not is there any one handing out roses and computers to consumers in both places. Instead, international production and trade is determined in the marketplace where supply and demand rule. Is there any reason to suppose that the potential for mutual gains from trade will be realized? Will the united states and south America actually end up producing the goods in which each has a comparative advantage? Will the trade between them actually make both countries better off?