The answer is simple - no, bitcoin will not kill banks!
Why? Because governments will never allow an uncontrolled entity to replace a government-controlled, formal payment mechanism. The only thing that bitcoin, as a technology, can influence, is to push banks to use part of blockchain technologies in banking technologies.
I agree, I get that people can dream whatever scenario they may like but we need to be realistic here, the goal of bitcoin has never been to kill banks, the goal of bitcoin is just to offer a currency with a scarce supply that is permissionless, that is it, anything more than that is nothing but a dream.
Governments are never going to allow this to happen and banks instead of remaining static and accept defeat will just adapt to the new reality just as they have been doing for hundreds of years, so while a world without banks sounds like a good idea to some it is never going to happen.