As long as these countries still really care about their country and their own currency, of course they and their currency will never disappear. Because this really depends on the concern of state officials who are willing to make efforts to maintain their country and its own currency in the long term. And if this year everything expressed by the OP is still there based on predictions four years ago, that means it hasn't disappeared yet and there is a possibility that it will persist for a long time.
The sovereignty of a country is also determined by its independence, which can be exercised without interference from other countries, including determining its own currency for the country's economy.So it is not easy to intervene in a country's sovereignty by changing or not recognizing its own currency, unless they are colonized and used as a source of war.but until now nothing has happened, and nothing has ever happened with that, other than perhaps providing flexibility for the use of US dollars, etc. to be accepted and used as a legal transaction.