I have different opinion. Don't call me crazy but to my mind Bitmain is the company which plays huge role in it too. The only reason of not dropping price below 5000 usd is that mining won't be profitable. Now imagine Bitfury and other companies, they all want profit.
So major thing is mining + people's psichology is only looking for rise, not for fall, if 600 usd was normal last summer, now it will be shock.