Okay, let's assume most of their steel is Chinese (I have my doubts because, yet again, more conspiracies), we only import a quarter of the steel we use. That would hurt losing it overnight, sure, but we wouldn't be absolutely toast like the autarkists are saying.
These takes are much more doomer than I'm willing to bet the supporters of "bring everything back" realize. Do you have no faith in the US economy / populace adapting to a hypothetical all out war with China?
Have you heard about the great toilet paper scarcity of 2020 during covid? and facemasks? US couldn't make either toilet paper or facemasks or ventilators or build hospital beds or anything that matters when the entire economy was at risk of shutdown.
I have a feeling that China doesn't export much steel. They more likely export their steel in the form of finished products.
Personally I have little to no faith in the adaptability of the US workforce for such things. It would be a generational shift. Exceedingly few people even have basic mechanical skills these days.
It’s not like WWII where you have a majority population that works on the farm or in a factory with their hands, and at home fixing stuff that breaks. That sort of population can be rapidly redeployed. We would need to start from the basics like “how to turn a screwdriver” for a huge portion of the workforce.
When you really start looking into things, nearly everything points back to China at some point. Pharmaceuticals? The APIs or at least important precursors largely originate there - even if they hit a middleman country first. Then you get into basic components and it’s the same story. That part from India or Mexico might not be available without China as a backstop.
It’s not an impossible problem, but it’s a problem that took decades and a generation or two to destroy. It’s far easier and quicker to destroy things than build them.