>>has been won by China, the moment it owns the major portion of US’ debt.
Nonsense. The difference between owning and controlling (which you have either missed or are obfuacating) to the side, it doesn't work like that. China could cause issues by releasing it all on the international market at a substantial loss - but they'd have to take the loss. Which they can't afford. Also, a move like that could easily incite sanctions from the countries hurt, plus the US, which is not dependent on exports. The US is close to self sufficient; it opened its market internationally as a move to block the Sovs (Bretton Woods) but it doesn't need it for its own economy.