"We make plenty of stuff at scale."

Not the stuff that matters (chips, electronics, metals, etc). We don't even have a primary lead smelter, which we would likely need if we got into a peer conflict.

It's also important to note that the US lacks the ability to quickly pivot and set up plants. Much of the knowledge to do so has been disappearing as employment in that sector has been steadily declining for decades. Sure we make stuff at scale using automation, but that automation can't be changed to significantly different stuff in a reasonable timeframe.