Adjustment to resolve asymmetries should be symmetric. Both sides should adjust. But sometimes it isn't symmetric. One side may choose to adjust; but the other side is forced to adjust. Like under the Gold Standard.
So if the Eurozone does break apart to resolve the asymmetry: I think it will not be through Germany choosing to leave; I think it will be through Ireland, Greece, wherever, being forced to leave.
Suppose people are different, so some people borrow from other people. And suppose this continues, and debt eventually gets too high, and needs to stop rising, or even come down. The creditors should spend more, and the debtors should spend less, so that total spending should stay the same. The adjustment should be symmetric.
In a barter economy, it might even happen like that. The creditors would decide that additional loans to the debtors would be unsafe, so decide to stop lending. If they don't lend, they have to spend their income themselves.
But in a monetary economy, it doesn't happen like that. The debtors have to reduce their spending, because nobody will lend them money. But the creditors don't have to increase their spending. They can continue to save, and accumulate money. The only way total spending can stay the same is if the creditors choose to increase spending. And that needs something, like a fall in interest rates, or monetary expansion, to persuade them to increase spending.
And if the creditors aren't persuaded to spend more, while the debtors are forced to spend less, there's a recession.
The same asymmetry of adjustment was a problem under the Gold Standard. Countries with a balance of payments deficit were losing gold reserves. They were forced to adjust, or else their gold reserves would eventually run out. Countries with a balance of payments surplus were gaining gold reserves. They could choose to adjust, if they wanted. Or they could just continue to accumulate gold reserves indefinitely, by sterilising the gain in reserves. (Sterilisation would mean the central bank would sell bonds in the open market to offset the gold it was buying, and so prevent its money supply from expanding, which short-circuits the natural adjustment mechanism.)
Keynes worried about this asymmetry, but Bretton Woods never really resolved it. It's one of the reasons that Bretton Woods fell apart. Countries that ran chronic balance of payments deficits sometimes were forced to devalue. I can't think of a case where a country that ran a chronic balance of payments surplus was forced to revalue. Because they weren't forced to do anything. (Though one of the reasons Canada chose to adopt a floating exchange rate in 1950 (pdf) was to allow the Canadian dollar to appreciate, which might be a partial exception?)
And I think that very same asymmetry is at work in the Eurozone right now. Germany should adjust one way, with higher prices, higher spending, or by leaving the Euro. And countries like Ireland and Greece should adjust the other way, with lower prices, lower spending, or by leaving the Euro. But Germany can choose to adjust. Ireland and Greece are forced to adjust.
Leaving a common currency like the Euro is much harder than leaving a fixed exchange rate regime. It's even harder than doing what Argentina did. But if there's a financial collapse anyway, and if a country is forced to issue a new currency just to pay the bills, it can happen.
It's unlikely that any country would choose to leave the Euro, simply because the transition costs would be so high. But some might be forced to leave the Euro. And that won't be Germany.
(Of course, you could say that anything we do is a choice, if the alternatives are bad enough.)