In this interview, he says that, unless major changes are implemented, the Eurozone collapse will happen. And, as I understand it, rather soon:

STIGLITZ: Italy could be the 'cataclysmic event' that leads to the fall of the eurozone

"That's going to be the end. What's going to happen is that there will be a definite consensus that Europe is not working. The diagnosis will be to shed the currency and keep the rest, or that Europe is not working and a broader rejection -- like in the UK.

"So my worry that this is precisely that kind of political event [something like Brexit] is that is what will be the catalyst for change."

Asked if he believed that the ongoing problems -- both politically and economically -- in Italy could trigger such an event, Stiglitz agreed, saying: "That is a big risk. Many people are now trying to work with Matteo Renzi [Italy's prime minister] to have him climb down from his commitment that he will resign if his referendum fails."

"Dieu se rit des hommes qui se plaignent des conséquences alors qu'ils en chérissent les causes" Jacques-Bénigne Bossuet