There is a big possibility that blockchain can replace banks. But that may be happen in the next year or maybe century, since blockchain market today is in crisis. Banks needs a stable currency and that needs the blockchain to develop.
Where is the possibility mate ? This is a technology and not like it will just start displacing banks since banks themselves as time goes on will end up finding a good use of the blockchain technology itself. The issue here is that a lot of people certainly do not understand what blockchain technology means exactly which is why they keep saying it can replace banks.
It will only change the way we spend, banks will always have a way to function with or without blockchain technology and as it is, I believe they will tend towards adopting the technology itself. Moreover, just like a lot of people have said, this is something that is not even worth debating in the first place because there is no way blockchain in itself disengage banking system from being operational.
Banks will still be able to find a way to adopt the usage of blockchain technology, find easier ways to do things and then we will see them still kicking well and fine. People should tend to discard their dreams about banks going into extinction in the long run because it wont happen.