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...
The introduction of bitcoin also offers new services to offer by the banks. There are services of banks that could I found usable even in the introduction of cryptocurrency such as loans. Banks could use blockchain to improve their services without getting engage in yhe industry. In conclusion, banks will survive and definitely will evolve and Im excited about this.