You forget economic policy is set by the Fed (an international conglomeration of bankers): if our currency was issued by the government instead or backed by ALL common commodoties (GDP-Gold+Silver+other metals) then you would be correct (Americans are industrious), but in the words of milton friedman “The Federal Reserve caused the great depression”- they may do it again..
Since there was no prior depression, the fed’s had no idea of their actions. I doubt they would repeat. With the war and current events, there would be riots in the streets not food lines.