As the financial world holds its breath ahead of Greece's pivotal elections this weekend, some believe it's time to write the obituary on the grand monetary experiment known as the euro.

Can you blame them? After all, the scary financial crisis is threatening the eurozone's very existence, forcing companies and policymakers to discuss the once unthinkable exit of one or more countries.

"Yes, the euro is a failure because it lacks the institutional structure to deal with a major crisis should one arise," said Jack Goldstone, a senior fellow at George Mason University. He said the eurozone is "sort of like a beautiful sailboat that runs fine in smooth wind, but has no motor if you are becalmed and approaching a reef."

Even Alan Greenspan, the former chairman of the Federal Reserve, is publicly questioning the sustainability of the euro.

In a speech this week in Montreal, Greenspan said Europe's "noble experiment" for a monetary union has been a "failure," pointing to the incorrect presumption that Greeks would behave economically like Germans simply because they share a currency.