American supremacy was due to the previous superpowers smashing themselves against each other, and then being relatively poor for decades after while rebuilding the continent.
Sure, but we also spent time, money, and effort building a unipolar system and getting buy-in for that from Europe as a considered strategic choice. To turn around and then say “they’re freeloading” when the policy of the United States was to encourage them to freeload so we had unfettered control over large sections of the world’s geopolitical policy - yes, they took the deal we offered.