It's not just about responsible policies now, it's about responsible policies later on. I believe without question that the Greek politicians are willing to spend countercyclically - but will they save countercyclically as well? A policy that just kicks the ball thirty years down the road is not a good one. And Greece has a long (andd proud?) tradition of defaulting.
But, to not invite accusations of negative criticism, here's a couple points to improve the state of the Greek state sustainably:
- Instituting an efficient and effective way of collecting taxes
- Earnestly going after tax evaders (no, even the new government hasn't done that yet)
- Making the administration more efficient, and not rehiring superfluous people
- Taxing shipping line owners - they currently don't pay taxes at all
This is by no means an exhaustive list.
Enforcing these directly would rightly be called an invasion of Greek sovereignity, so any incentive from outside has to be indirect: Either they save money by the obvious means - spending cuts, tax hikes -, or they get their shit together and reform. And I firmly believe that after these reforms have been conducted, or at least credibly pursued, the rest of the eurozone will agree to some sort of debt reduction - reluctantly and with great ostentative wailing and gnashing of teeth to keep dumb voters like me satisfied that justice has been served and the order of things kept.
The post-WWI haircuts for Germany went the same way, by the way: First there was the Erfüllungspolitik, the 'policy of fulfillment' which was supposed to show, by giving it its best shot and failing, that Germany was simply not able to pay the reparations, and only after that did Germany get the necessary relief in the form of the Dawes Plan. And when it turned out even that was not sustainable, the Young plan was adopted, and after that one failed because of the Great Depression, the Nazis came to power and here the analogy breaks down.
My point is that we don't need an Endlösung right now: It's sufficient to have a medium-term plan, let's say for the next five years, that's
fairly acceptable for all sides. And in a couple years, when the situation has changed, the new and old issues can be adressed for the next five years, and so on and so on. Sure, this trades long-term certainty for short-term calm, but it would certainly be more beneficial to the Greek economy and people than the mess that's been created IRL.