I generally agree except for the war. Personnel costs, energy, manufacturing costs, costs of specific weaponry used vary vastly across countries. Russia or China can deliver much more firepower per USD than US.
Because the US fights global wars, it focuses on quality over quantity, as logistic costs start to dominate the production costs of military power.
If China tried to fight some Iraq war, it'll be just as expensive as the US effort. Even soldiers have to be paid far more in offensive expeditionary wars than defensive homeland wars, just to maintain morale.
One exception is mercenary groups like Wagner, they are actually extremely cost effective. That's because of much more flexible management structure, using private enterprise structures instead of rigid formal militaries, works 100 times better for chaotic low intensity warfare.
Maybe once - the shambolic internal politics playing out with the funding for Ukraine (a lot of which stays in the US anyway) doesn’t indicate American power. Quite the opposite.
The US has environmental policies that increase the cost of energy, but in a sufficiently serious war, those would get suspended.
Personnel costs though are vastly higher in the US especially if "costs" included the political costs of instituting a draft.
That said, in a sufficiently serious war, IMO there'd be homeland attacks on critical infra, be it cyber or long range strikes, so it's really about who can survive/operate/recover from capex attrition fastest.
PRC domestic consumption is 14m barrels per day.~6m goes to transportation, 2m goes to heating, both in process of being electrified. 2m goes to other. Industry, uses ~4m barrels, of which PRC MIC uses relatively little as % of output. They can sustain military multiple their current size on wartime economy. There's also estimated 300m barrels and growing in strategic reserves,.
Coal is useful in that coal gassification useful to make fertilizer. Which PRC did - they were NET fertlizer exporter ~10 years ago before they clamped down on coal and curtailed sector.
Utimately it's not just a US+co navy+airforce vs PRC navy+airforce fight, it's a whatever US military logistics can bring in theatre vs entire Chinese industrial homefront pivotting into MIC fight with their various PPP advantages using domestic inputs, which is looking more and more to be more substantial relative to what US+co is projected/planned to muster.