Even so this is not a reassuring argument for the future of the Euro:
The fundamental problem of the euro is the lack of a fiscal dimension. Successful currency unions, such as the US, have mechanisms for fiscal transfers from members that are thriving to those that are struggling.This is completely true, but whereas people are willing to allow their money to be taxed in order to subsidise their compatriots, they are unlikely to be satisifed with transfering billions of Euros a year, for decades to come, to give to foreign countries. Every time a country that is a net recipient of fiscal transfers institutes some kind of benefit for their citizens that a net contributer does not provide, tensions will be inflamed.
Given that the theory behind currency unions was already well known in the 1990s, there is a reason why the architects of the single currency were unwilling to take that necessary step to ensure the project's stability.
It seems like a recipe for promoting nationalistic hostility between nations.