Of course automation plays a part, but it is nothing like the whole story. China now has far greater capabilities to make critical components from chips to solar panels than is located here. Look what happens to our supply chain when supply is just reduced a bit. What do you think would happen to our economy in a conflict?
>>China's history of planning has led to tons of misallocation of resources, and I'm not sure I'd want to emulate that.
Of course we wouldn't want to emulate that; that's a strawman argument.
But to use that argument to avoid planning altogether is foolish. And yes, resources will APPEAR to be wasted. Keeping more than minimal capabilities immediately at hand is "inefficient".
This is the same as exercising and eating right to stay in good physical condition - no one needs to be able to lift weight and run fast for 99.99% of modern jobs. Yet it is a good idea for many reasons. By your argument, why bother to save for emergencies or tough times? That's inefficient - you should enjoy your full income right now - heck, go into debt too!. Also by your argument, we shouldn't plan to avoid technical debt - that's inefficient waste of programmer time - just write the first thing that comes to mind to deploy the feature.
Most of those jobs outside of a few narrow categories were lost to automation. We make more steel, aircrafts, and cars than ever but with far fewer people.
China's history of planning has led to tons of misallocation of resources, and I'm not sure I'd want to emulate that.