I think that anyone who's seen what the EU/Eurozone/ECB/Comission/Eurogroup did to Greece knows that staying in the EU is not in their interest at all.
Sure, the Troika and the EU (especially Germany and France) chose a path that created a lot of suffering for the Greek people in the short run, but bear in mind that Greece brought itself into this position by agreeing to become a part of the Euro zone and doing so using highly "creative" ways to mask their bad metrics to fulfill the stability criteria. If anyone is to blame here it's the EU for taking Greece into the Eurozone and the Greek government back then for eagerly grabbing that opportunity while ignoring (or not knowing) the risks. What we should learn from this is that strong political will alone is not sufficient if the underlying fundamental economic values are wrong.
No more than 5-15% ever passes through Greek hands.