Greece is no longer an export-heavy country at all; so while some companies may benefit from competitive rates due to a devalued currency, the vast
majority would not. When you balance the amount of cheap exports, compared to more expensive imports, it's not worth it at all - especially when you would be gambling with the lives of around 10 million people.
Also no, Greece don't want that either.
The Eurozone is the largest economy in the world; Greece leaving could be devastating to it due to its infrastructure not being designed for members leaving and it could be far worse than the Lehman brothers collapse; such as leading Germany into recession and inflation in other Eurozone countries, as well as big problems outside of Europe to the intricate nature in which economies are wound together.
Greece can not do an Argentina because they don't have their own currency to devalue; it would take 7-8 months to make one and then devalue it. How can they last that long without money? Simple - they can't. People won't be putting Euros in the bank due to fears of them turning into weakened Drachmas over night. Distributing them to ATMs etc would take a really long time and the entire banking system would have to be reconfigured. Germany has stored Deutsch marks, but Greece has destroyed all Drachmas so there is none in reserve either.
If you're dying, cutting off your arm won't stop you from dying. The problem is not with one individual part of the system; it's with the system itself.