Without a debt cut, leaving the euro is probably the next best option. But it's completely understandable that Greece is hesitant to do so. Once they are out, it'll be a long way back in, should they ever desire to do so.
In that case they should have never started with their referendum shenanigans. They should have tried to be professional over the last weeks and months by actually submitting real proposals on time, and not a few hours before meetings. That was the time when the traditional looking-for-a-shitty-compromise negotiations were still what everybody wanted to play.
Once the referendum was announced, everybody lost interest in reaching a deal. If you are willing to go that far, you should be willing to go through with it to the end. Trying to go
back to where we had been two weeks ago was just a silly move by Tsipras. And one that pisses on everything he has said about democracy during the referendum.