The American dollar have been the official legal tender of the world for almost two centuries and if there will be sufficient reasons as to its fall then there is no surprise since that is the natural flow of currency and economics. If in case it will fall then we must prepare and consider as to what fiat currency will replace its seat when it falls into ruin.
I disagree with you. The main increase in the prevalence of us dollars in the world was after the second world war. This was due to the fact that the economy of many countries was destroyed and America has imposed its own dollar. Until 1925 the dollar was guaranteed by gold and diamonds is also appreciated, but many countries have had the opportunity. After the second world war, everything changed. Maybe after the third will also change.