In 1946, United States reigned supreme militarily and economically, relative to the rest of the world.
today in absolute sense, United States is far better place economically that it was in 1946. Its military unmatched in a great power contest, but in relative global sense the United States has been in relative decline since 1946, compared to the rise of Asia etc. And there is nothing one can do about it. Just good ‘old reversion back to the mean.
That is just China and the rest of Asia catching up to their economic potential from a low economic base on the back of their large population. And I think that should be celebrated. The fact that the rest of the world will be enjoying higher standards of living is great thing net-net for humanity as oppose being concerned about the potential of US economic global domination being eclipsed. And that not everyone is going to like Mikey Mouse.
In any case, these two notions ought not to be a zero sum game or mutually exclusive.
If the great power of today cannot adapt they will be swept aside. Nothing last forever.