If you look at oil prices, the Iran-US-Israel-Saudi war is now everyone's problem globally, whether they're part of the hegemon or not.

It's very difficult to disconnect from the problems of the world when your fuel is imported (+) from the middle east and your chips are imported from the Far east. Trying to be an autarky is .. well, the US might be able to do it, but it will be fearsomely expensive.

(+) US is currently a net exporter of oil/petroleum products, but that is a recent development and subject to change

The biggest to suffer after the BAM is closed is the EU. It is not an accident that the USA decided not to support Saudi when they asked for air strikes last week.

ARAMCO just told the EU there will be no oil shipments next month.

Hurting the EU is a major goal of the current US admin.