While exiting might be good in the long run, you make it sound like it will be all right. If they exit, Greece will suffer worst and will need humanitarian help to save it's citizens.
Remember, Argentina still can't raise capital from market even after more than a decade.
Argentina was quite capable of doing that just right before their legal case with a few predatory holdouts made life for the government difficult again.
To be fair, it was an incredibly mismanaged trial (both by the defending lawyers and Cristina's insane and confusing statements), and the holdouts in question are essentially the scum of planet Earth, purposely speculating on junk bonds and always going to trial for profit.
Despite that, both national and local governments have been raising capital to the tune of several billion dollars. Of course, the interest rate is insane, but that's more of a question of the government's disastrous capital control policies; serious private investors were not convinced that the default over the holdouts' bonds is too relevant.