The countries in the euro zone undertook a massive effort to integrate their markets for goods and services, capital, and labour, and to harmonize their fiscal and regulatory policies. Only after all of this was in place did they move to launch the common currency. It would not have made economic sense to go through the process in reverse.
It would not make sense in North America either. We would first need to more  2  BIS Review 56/2002  closely integrate trade in goods and services, and, particularly, our markets for labour. Only then would it make sense to deal with the currency issue. Concluding comments As I said at the beginning, this is an important topic for discussion and research.