Mark Grant, via ZeroHedge, actually takes us through the math of Greece, which is a proxy for the other failing countries.
A Greek exit would cost €1.3tr! Once Greek left the Eurozone, the other countries would begin exiting, too, in order to avoid holding the bag. You see, once a country leaves, it raises the liabilities of the other members.
This dissolution and the resulting chaos cannot be allowed to happen. Therefore, the euros will do anything to avoid this outcome. Greece will continue to be strung along so that ECB losses on its debt do not have to be recognized. In fact, I think Spain will get the same treatment. It will get just enough aid to keep it going.
What could interfere with this plan is social unrest. If the people decided that they have had enough austerity, then the ruse is over.