Banks won't get disrupted by the cryptos anytime soon because the whole system / society is relying on them, moreover Bitcoin and cryptos are only accessible to people connected to Internet (approx 50% worldwide), so what are you going to do with the other 50%? There is also a big part of the population living in developed countries, with internet connection and all the equipment that you would need to use bitcoin and that would not want or simply understand a possible new bitcoin system (old people, non-digital-natives and many others) replacing the fiat currency system, just look at the EU, when countries changed from their local currencies to the Euro, it took years for people to understand what was going on, so imagine for a digital currency like Bitcoin.
As the situation is now it seems quit impossible because the bitcoin is currently known by less than 5% of the world population, and it could possibly be accessible to 25% of the world population admitting that everybody would know that this technology even exists.
That is why I don't believe in the end of the banks, the fiat/traditional market will still be too big to hope anything like that in the next 50 years, but assuming that bitcoin will go mainstream I am sure that banks will adapt the retail banking to the crypto industry.