I used to think this, but lately I'm not so sure. Beyond financial services, What does "the entire world" rely on US for anymore?
I know it's a controversial doctrine, but power projection does have a hand in keeping the peace.
That's a very US-centric POV. It's not like half the world would suddenly cease existing if the US collapsed.
people would lose access to Teams and Office
but who cares, there's plenty of substitutes
Beyond the hoses and water what do we need the fire trucks for?
Our market.
And the sanitation.