They're not scared. There's just not any real threat just yet. Environmental factors such as political and regulatory support, widespread social buy-in necessary to create network effects, and even a proper technological base are still very much in the banks' favor. Real adoption of a crypto-currency based payment system for example is only realistic if the banks build that system themselves. There's no incentive to cannibalize their existing business though. Not at the moment anyway.

They're definitely not clueless either. All of the big banks have published studies on the topic. Some of the analysis seems a bit crazy (UBS's paper from April 2014 was done by their equities department and seems delusional) but most of it is thorough  nevertheless.