But the US doesn't have the kind of centralised strategy or funds to stockpile enough anything to sustain an actual war with China.

By gleefully engaging in mercantile trade, China has made the US dependent upon it, and the US just can't start a war it could begin to win. Nor would the bourgeois class want to tolerate it for long because of how much it cuts into their own profits (which is clearly why they're giving up on tariffs now).