Your thinking making and slapping parts together is all it takes. There is so much behind the scenes stuff that goes on for even the simplest product. Market research, design, testing, supplier management, project management, etc. Then you add in all the levels of management, HR, Accounting, payroll, etc you have more behind the scenes jobs as the assembly plants. Those jobs are higher skill and in the US higher pay, but not in the other countries. When all of those jobs are outside the US and the corporate headquarters is outside the US they save so much they can afford to overpay the assembly line workers. So many people are blind to the rest of the world and believe the "made in the US" marketing from those brands without knowing how small a part of "made" there really is.