That is a good point, and one I've made in other threads.  Though I don't have hard numbers, I suspect the drug trade (and other illegal dark market stuff) accounts for a big part of the bitcoin economy--but I could be wrong.  My thought is that some other coin might take over, maybe something with more anonymity.  I'm actually kind of surprised that Dash or some other coin that's harder to trace hasn't been the coin of choice for ransoms and the dark market transactions. 

This most recent crash could just be the huge correction that a lot of people, including myself, have been expecting.  We just rose too high, too fast, and this was not only expected but inevitable.  And I think we'll be rebounding pretty soon.  This is bitcoin traders taking their profits off the table, which happens in every market.