Trump can't make companies manufacture stuff in the US
If Apple/Dell/HP was somehow forced to make iPhones/laptops in the US it would be done in a huge factory filled with robots. He seems to think you can turn back the clock to the 1950s, but unions were much stronger back then (and it is his republican party that is primarily responsible for weakening them) so factory work in outside of the remaining unionized industries like automobiles are low wage.
Probably most US citizens wouldn't want a $10/hr job standing on an assembly line 8 hours a day fiddling tiny bits into phones or laptops. There are plenty of people who would take a job like that though south of the border. The same people who take the jobs Americans don't want in California's orchards, or the meatpacking plants in the Plains states, and so forth.
The problem is even at $10/hr it would be cheaper to do with robots, which is why the process is slowly becoming more automated. If Steve Jobs was still alive I'd be willing to bet iPhones would be made in robotic factories today - he was always enamored with that idea and had a super high tech factory at NeXT that used a lot of robots. Unfortunately it was decades too soon for that and one of the reasons NeXT couldn't turn a profit.
Biting the hand that feeds IT
