>>212789104US has a population of 340 million people, and their auto industry accounts for $1T. Not only do they make their own cars, they also have high tariffs on international cars, so they have to be manufactured there.
Also, Boeing+UT+Sikorsky+Northrop Grumman+Raytheon is another $500B.
Just cars + planes/defense is 60% of US's manufacturing.