That is absolutely false. There is no such requirement and they are already trading in non-dollar denominations. This has been happening for years now. The genie is already out of the bottle. You're fooling yourself.
You are the one under a delusion. There are vast amounts of money in dollars flowing around the globe that would have to be replaced. The trading you are talking about is miniscule in comparison. It has been around for years, as you say, and has not gained much traction during that time. There are also Bitcoin and SDRs, and dollars may be replaced one day, but it ain’t going to happen soon.