This isn't backed by evidence, it's at best speculation for some potential future at least 4 years, but probably closer to 10, in the future. Most industries cannot simply just spin up new factories at the turn of a switch.
There was a good post here the other day on bicycle manufacturing that pointed out that, while cheap, high volume, low-end products may indeed be practical to manufacture in the U.S. primarily for the U.S. market, it may not make sense to manufacture many high-end products behind trade barriers. Such products have low margins and need free access to the world market to make sense to build. Those that are currently manufactured outside the U.S. will likely stay outside the U.S. while those made in the U.S. may have to consider moving. Some will likely just no longer make sense to import into the U.S., leaving a void in that market, and some won't make sense to build at all.
Breaking the world market up into regions, as the U.S. is currently attempting, reduces the world's ability to make specialized, low-volume products.
There are two arguments in favor of free trade:
1) We don’t want to spend expensive american labor building X.
2) We don’t have the industrial capability to build X anymore.
The latter seems to be a damning indictment of the former. It’s one thing not to build X domestically to save money. It’s another thing to lose the capability to feasibly build X in the US because you have outsources that capability and lost it.
I’m sure if we ever got into a war with China, they’d wait for us for a decade to rebuild our manufacturing capacity.
You're quite optimistic. With the current administration and its purge of federal workers (including those in NIST), it will likely take much longer than that.
You missed the single most common argument in favor of free trade:
1. Everyone has more stuff than otherwise.
Under free trade, total world production is higher.
There can be winners and losers of free trade, despite more aggregate production. I dont personally think we were there, but it is a possibility.
It isn't; if we had lower labor costs than everywhere else, free trade would still have the same effects.
Particularly given how wild this administration is. Who knows what the situation will be tomorrow, even! America is increasingly perceived as a wildly unreliable partner.