BTC and banks already work together. In the USA
Wells Fargo works with coinbase
PayPal works with syncronitcy bank and coinbase.
and Citibank works with Coinbase.
They don't work together, Banks work with other services that provide services to customers owning Bitcoin.
By the same analogy, Well Frago works with euros or Mastercard works with Coca-cola because you can buy an of juice with a card.
Bitcoin is a tool, everyone can use it as they see fit, that's the beauty of it, but a tool doesn't decide a thing, it can't act on its own and it can react to something, that's why no matter what a cryptocurrency will never be able to replace a central bank since it's not a sentient or run by a sentient being. Gold has not replaced central banks, quite the opposite, nor will Bitcoin.