They won't, at least not as the PR stunts promise. The finances don't work for a variety of reasons. This is one of the ruses that politicians play. Hold a presser promising thousands of jobs, give away millions in tax dollars, if not billions...then, nothing.
Recall the Foxconn fiasco. It's a story the continues to be repeated. Photo ops with shovels, 1/10th of the promises are delivered, if that. For instance, during the last Trump administration, he touted steel tariffs as a huge win because there was a slight uptick in US steel jobs, but that was outstripped by job losses in steel-related industries. It was a net loss - certainly nothing to celebrate.
There certainly will be some industries that already have infrastructure in place may decide to ramp up production on a temporary basis, but that's window dressing. Car manufacturers, for instance, could increase production on a line or two for a short time, but it won't be a repatriation of production.
I do understand the emotional element of this and I am not going to discount that factor in the decisions that are being made, because it appeals to a large portion of the voter pool. The US, historically, was a big producer of goods and entire regions were propped up by those industries and people long for the same environment.