I guess not. Banks will not let this happen. If blockchain will be very useful and be worldwide use, banks will just adopt this new technology and innovate a new way how to use it more effectively. Also most of the people still seeking the traditional ways of banks because the are sure about the security of their money with. Let be honest, blockchain can still be penetrated by hackers because its still have its own weaknesses. But blockchain is still the future of banking and money.