I don't fully understand all the dynamics, but you run into the https://en.wikipedia.org/wiki/Triffin_dilemma https://en.wikipedia.org/wiki/Triffin_dilemma if y

I don't fully understand all the dynamics, but you run into the https://en.wikipedia.org/wiki/Triffin_dilemma https://en.wikipedia.org/wiki/Triffin_dilemma if you want to be the world's reserve currency while simultaneously possessing a competitive manufacturing and exporting sector. So even if the US hadn't been involved in the war, its industry would have been hamstrung and unable to compete effectively due to a strong dollar.