what happens if bitcoin builds a bank just like a bank with a headquarters, savings account management and also makes a bitcoin account card ??
bitcoin is not a person to build a bank.
bitcoin is not a centralized group that can build a bank.
anything that is made is made by third parties like you and me.
nothing happens when others offer different services such as wallets (coinbase, xapo,...) exchanges (bitfinex, poloniex,...) gambling sites (....). so nothing will happen when someone offers a "bank" services too.
what did you expect to happen anyways?
hav you seen blockstream lately..
they OWN the github and control what happens
the "you and me" you talk about have tried to do bips to upgrade the network and within 24 hours a blockstream employee has closed the bip/issue.
its time you get your head out of the sand thinking bitcoin code is not controlled and the gateways in and out of bitcoin are not controlled.