If it happens, it won't be for some time. Too many big businesses with huge amounts of money sheltered against taxes there and too much manufacturing moved over there.
Well beyond the plants here being closed for a long time, there are a ton of skill sets lost due to not being passed from worker to worker.
A good example I can give was the electrical generating station I worked at had to replace the "Main Power Transformers" for various reasons. These are the transformer that take the output from the generators and steps up the voltage to the electrical grid.
They had to source the new transformers from Spain which also required them to be modified to work with our systems here.
I say "had to" because there's no place left here in the US that makes these big transformer and no one left who even knows how. The old ones made 80+ years ago were built to last. When the demand for them dried up, they quit making them, closed the plants, and lost all the tribal knowledge. All that info and knowledge used before the creation of the digital age lost to time and decay, the workers very aged or dead.
I can still remember all the new engineers coming to the control room and seeing all the old analog relays. Fresh from college and they had no idea what they were even looking at, no longer taught in schools.
