Indeed, they will run out of business pretty soon.
It is
not for nothingno coincidence that banks are considered the backbone and pillars of any
country's economy. That means if the bank goes bankrupt or goes extinct, the economy will collapse too. Do you think the government and central bank will let that happen? I don't think they'll let that happen, and I don't believe crypto will become so important that they can decide the economic fate of a country. So there will never be a case of a bank going bankrupt just because they don't adopt cryptocurrency.
Banks may face challenges if they don't adopt cryptocurrencies as they become more popular, but banks never go bankrupt. I am sure of that because banking plays a core role in the economy.