Most of the manufacturing we still have is either high tech required more education, or robotic requiring fewer workers. High labor manufacturing left about 20 years ago with sewing, shoe making, and textiles. Electronics left because of the skills improved overseas, and the factories could be smaller. Japan has lost a lot of their manufacturing to other Asian countries. Once a country is saturated and labor prices increase, the factories will go to other countries like India, Indonesia, South America or Africa. I do think we need to keep a sample of all types for national emergencies. For instance, have all military uniforms, boots, gear, etc, manufactured here, including all weapons, and electronics. We still also have an abundance of natural resources here, 800 year supply of coal, 200 year supply of natural gas, 200 year supply of oil on government land and offshore, enough wind in the plains states to power the entire country, 90% of the worlds copper is in the US and Canada, also uranium, abundant farmland, lead, iron, limestone, granite (with is 5% uranium), etc.