The reality is that they are powerful but if they were to become actice participants in some hypothetical war the governments could freeze and withold funds with the swipe of a pen.

There are a lot of regs around the freedom of funds and stopping that if there is a legitimate national security risk. The US is doing it right now with funds provided from the EU to purchase weapons for Ukraine. The US is not fulfilling orders because they blew their load murdering innocent children in Iran.