The banks are providing services to people from years and will continue to provide then for years. They have their place and functioning of their own and they don't fear these cryptocurrencies.They are very well aware about ots usage and have already taken steps like adopting blockchain technology and developing their own digital coins backed up by assests like gold.If situation like people using crypto more than Fiat come Banks will Coexists with them.But future has many surprises for all of us let wait for it and hope its better.