The idea that cryptocurrency replaces banks would be a revolution. This is an alternative to the liquidity process that has been widely accepted around the world.
I don't think crypto will replace the bank, in my opinion crypto's participation in this case is to improve or be the development of technology in banking to manage safer and corruption-free finance
Yes, crypto and blockchains in particular will offer some tools that banks will use to offer or expand their services and only for certain customers (retail customers, I think).
If you think banks can't adjust to new world whenever bitcoin and crypto gets huge than you have never seen banks do any shady stuff. These are the dudes that got bailed out 800 BILLION DOLLARS when world economy collapsed like no other.
If crypto gets big enough I am pretty sure banks will still find a way to make money from it and I am pretty sure the banks will also turn into crypto banks as well and manage to get to trading and investing to crypto for their customers and make sure all the SEC stuff is old times story where crypto is purely legal and very little taxed for investment yet highly taxed on personally buying so they could be the only option.