I suspect there will be at least two big ones on about the same level but I don't think this will be particularly near future, at least not near future in context of the global economy which is fairly young. It is the logical path for China with their role in the global economy and how much western business relies on them, but this will take decades, they have a lot of work ahead of them.

Do you even need singular global currency in modern world? Where every transaction can be in essence instant if there was desire. And everything is digital. Overall it is rather different world and things can be done different than before.

The world doesn’t necessarily need it, but the US does need it to be the dollar due to the massive deficits it runs.

The US dollar provides a massive stabilizing effect on the global economy, which we don't need but it is nice.

> Do you even need singular global currency in modern world? Where every transaction can be in essence instant if there was desire.

Pricing at international scale becomes a lot more complicated without a singular global reserve currency.

> Do you even need singular global currency in modern world?

The world doesn't need it, but unless Americans want to see their purchasing power destroyed, they do.