As far as I'm concerned, everyone is at fault. Previous Greek governments mostly. The Greek people also for only caring about their own self interest and voting along certain lines regardless of looking at policy. Don't get me wrong, we could talk about the corruption and inefficiencies of lots of other countries indefinitely, but the fact remains that Greece took it to a ridiculous level. And now they are paying.
The EU is also greatly at fault. How did they think loading up a nation that is already in the red, with lots more debt would work out ? Purely by austerity ? Please spare me. The experiment of "growth" via "deflation" hasn't really worked out. All the EU is doing and has been doing since 2008 is pushing the problem down the road. To Greece's credit they are saying enough is enough and we need a better way.
The only viable solution is growth. If someone has a 100K debt and you cut his wage from 50K to 30K he's not exactly going to be in a position to pay it back easily. If instead you get him a job paying 70K all of a sudden everyone wins. This is what Greece needs.
Unfortunately, this sort of mini Marshall Plan can't happen for political reasons. Basically, it comes down to whining and precedent. If the EU helps out Greece then everyone else will want similar help. If the EU helps out Greece then there is no incentive for Greece to get its s%$#! together. The EU must help Greece but the EU can't help Greece.
This is why in essence the EU as an economic entity is dysfunctional and always will be. It can't do what is require to "fix" things when they're broken. It either doesn't have the mechanisms or doesn't have the will. Giving it the mechanisms brings up issues of sovereignty which is a whole new ball game again.
Thinks will essentially stay as they are give or take a few tweaks. Maybe Tsipras might improve things here or there, but any gains by him or any government in the next 10 or so years will be small incremental gains. Better than nothing I suppose.
The only long term fix is the EU voluntarily breaking apart. Germany definitely never wants this to happen as the value of the DM would sky rocket and smash their export industries as well as the lost of prestige. No one wants to admit that a project they've worked on for decades is a failure.