(Bloomberg Opinion) -- There’s just no getting past the supremacy of the dollar, much as skeptics of American influence wish for it or lonely yen bulls cry for relief. The greenback has been frequently tipped to retreat, only for it to blow away everything in front of it. This resilience might not last, but as long as it does, it reminds a world once in thrall to China’s ascent that the US is the essential economic force. Just ask all the central bankers quizzed as much, if not more, about...