Comment by throw0101c

> What could replace it?

It doesn't necessarily have to be one thing. We've had multi-currency regimes in the past (before one generally took over). See How global currencies work past, present, and future by Barry Eichengreen, Arnaud Mehl, and Livia Chitu:

* https://press.princeton.edu/books/hardcover/9780691177007/ho...