This article is literally about the decline of american dollar dominance. i'm not sure with in denial is still at play here. There is a clear panic alarm in the US, look at the policies and attitude of the US. things are changing.
You have to put stuff in perspective. Despite the recent decline (which is still way above the 50% and much higher than the lowest it has ever historically been), the percentage USD has is still several times larger than the EUR in second place.
There could never be a common currency between them that they can't directly control.