I don't think this is imminent. There are powerful forces that want Greece to remain in the EZ.
This is a propaganda war. Right now the Troika is bringing down colossal pressure on the Greeks, and basically saying, like it or leave it.
But there are other deal options (including less austerity and more debt forgiveness), and also the leaders of the EZ can lift the limit on banking liquidity going over the head of the ECB.
It's a scare campaign that has run away with them...for now. It's still early days IMO.
