The US is large enough to have basically every material resource it could need. The problems comes from the cost/pollution of mining and refinement and the cleaner you are the more costlier it gets, and actually possessing the equipment, processing facilities, and experienced workforce to utilize those resources, which we have a huge lack of because we spent decades outsourcing most of that work. Again because doing it cleanly costs more money, and investors won't get as good of a return on their investment so outsource it.

Nobody invests in operations that only make a token profit when they could instead invest it overseas and earn a substantial profit.