"1000 Quatloos for the newcomers!"
It will be interesting to see how Greece gets out of their mess, when they run out of Euros. Pundits are guessing that Greece will issue "scrips", which are a kind of government IOU, and pay government salaries and pensions with them.
The only problem with that is . . . who will want these scrips? Certainly not even the Greeks themselves. They want Euros. And they will try to get rid of their scrips as soon as they can, in exchange for something of value.
Car sales are up now in Greece by something like 40%, as people worry about if their bank accounts will get raided by the government. An automobile is considered as something "valuable". The cruel irony here, is that Greeks prefer to buy German cars . . . exactly the folks who Greeks blame for all their problems. So the Germans are actually benefiting the most from this.
It's a non-problem. If a country cannot control the money supply they are left with few options to control their economy. Using interest rates and money supply a central bank can very strictly control all aspects of their economy (spiraling debt, runaway inflation, etc). Greece does not control their own money supply.
There will always be a weakest state in the EU; almost just by definition alone that weakest state will face trade deficits with the rest of the EU. With no way to control their own currency they will get weaker and weaker unless the rest of the EU keeps them afloat.
Lets say that the EU /doesn't/ keep that weakest state afloat... with no other option the weakest state will eventually be forced to leave the EU and start printing its own money (or scrips, as you referred above to them). This leaves the creditors of that state in the unenviable position of being forced to either forfeit the debt or accept the newly issued money at a certain exchange rate; a rate which will be set artificially high by the state purely to offset as much of the debt as possible.
The best chance the creditors have to get their money back eventually is to ensure that the weakest state remains in the EU... Because, you see, once that weakest state leaves the EU and discharges its debt with worthless scrip, there will be another "weakest state" in the EU! The process will then repeat for that state too, even faster this time because the new weakest-EU-state saw how the previous-weakest-EU-state got a whole lot of money from creditors and didn't have to pay it back!
So, now it's Greece; if Greece leaves EU without fulfilling its debt obligations to Germany, then the new weakest state might be.... Portugal? Someone, at any rate. After two years this Greece process will repeat with that new weakest state. And so on, until only two states are using Euros.
So the EU cannot do anything that will cause a country to leave. They know this. We know this. Anyone who's ever been a creditor knows this. You never let your debtor go bankrupt until after they've settled their debt to you.
After all getting *most* of your money back is better than getting almost nothing (or, in the case of Greece, nothing at all).
If Greece only owed a little then the EU might let them leave in a huff - the scrip they offer might offset that small amount they owe. But Greece owes a lot, more than the EU can afford to write off as a bad debt.
And all this because weak countries will be unable to focus their economies due to having no control over the money supply
TLDR:- There's a saying amongst capitalists, venture or otherwise: If you owe your bank $100,000 and cannot settle it then you have a problem. If you owe your bank $100 million and cannot pay, then it's your bank that has a problem. It's not Greece that has the problem, it's the EU!