As a matter of fact, the epicentre of the current crisis lies outside the euro area, and the euro area has not had to deal with the failure of a major financial institution or a bank run.
The economic framework they had in mind, known as the optimum currency area theory, predicts that the creation of a common monetary area becomes more costly the more the participating countries experience idiosyncratic shocks, in terms of size, nature and frequency, and the more varied their responses to such shocks are.