Like farming before it, manufacturing in the year 2004 is an activity in rapid decline in the US. But in 1949 the US still had perhaps 50% of the manufacturing capcity in the world after WWII had destroyed much of the rest around the world. As a result, the auto industry and others needed a large pool of people skilled in various aspects of manufacturing to suppy a largely captive market in the US, and a global market that would slowly grow.