Limited patriot missiles may not hurt the US too much in a war with China because China will likely overwhelm patriot batteries, and destroy those batteries in one day. Without batteries to fire the missiles, the missiles are useless.
One reason the US does not build that many missiles in a year is because the fuel in missiles degrades and makes the missiles too dangerous to fire, meaning, if we build a whole lot during peacetime, most of the missiles will go in the trash along with the piles of money it cost to purchase them.
“The first six days of war in Iran cost U.S. taxpayers at least $11.3 billion in munitions alone, according to Pentagon estimates reviewed by lawmakers, and experts say the ongoing cost could increase exponentially. That total does not include the cost of operating and maintaining the military force engaged in the war or battle damage sustained from Iran’s attacks.
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While initial cost estimates of the U.S. wars in Iraq and Afghanistan were around $50 to $60 billion, they ended up costing a combined $8 trillion, according to analysis by Costs of War.”
W Bush focusing on fighting insurgencies while China was rising, led to the US not having the military industrial base and stockpiles of certain munitions. If the US uses too many munitions fighting Iran, it will be greatly weakened for a fight against China. This also weakens US deterrence against China.
However, if Iran is in too much chaos to pump oil, or if it is friendly enough with the US that in the event of a China-US war it would not sell oil to China, that would be a huge advantage in starving China of oil in the event of a war.
“In addition to easing weapons transfers, the agreement will open Saudi Arabia as a location to store U.S. weapons, and make the country eligible to bid on Pentagon maintenance and repair contracts and purchase depleted uranium ammunition.”