In every business it's the same. When new technology comes up the existing businesses will evolve or die. And obviously new businesses will also rise strong.
Same happened with mp3 and music industry...
Banks will not be more efficient as of the past decades until a new era of currency system comes up. Crypto currency can hold and store money up to a such amount also it is more secured than what bank does, in synonymous manner banks and the new upcoming crypto's can be encrypted so we need to be much understanding.
It is right that crypto exchanges are going to eliminate banks from the world but it is not so easy and will take long time. I am sure that in the future banks will start exchange in cryptocurrency because people will use only cryptocurrency and all other currencies in the world will disappear from the market and fiat as well. There would be no need for fiat in the far future.