To an extent, yes. I'd say the difference is government systems. A single organism, or something like the human body, has more evolved, more sophisticated government mechanisms. The body is mostly a cooperative civilisation of cells. Of course, there's still natural competition among them, in many shapes and forms. The cells are held together in a coherent, agile, resilient organism by governance systems strong enough to keep internal Darwinism from becoming civil war.
This is just one micro-instance of a much larger thing. Brain encodes structural similarity across modalities. Corollary: language is far from arbitrary labels for things.
The exact point I'm making is that this is NOT the case! US has super strong financial control over most of the world in a way which is NOT connected to the strength of the US currency.
Is the US dollar losing its dominance? The answer is both A) yes and B) it doesn't matter.
Yes, US dollar is losing a bit of power and influence. This is likely to continue.
Making inferences about the US global dominance based on this fact is misguided. US global dominance is as strong as ever and, if anything, getting stronger. US has very successfully managed to move the game a level above currency, to direct governance via financial, legal, political and military means. It has made any meaningful competitors either entirely irrelevant (e.g. Russia), pretty well aligned (e.g. India) or pretty well contained (e.g. China) It's blue skies ahead.