Central banks are now the dominant structure that nations use to manage their economies. They have monopoly power and will not give up that power. While the adoption rates for Bitcoin and other digital currencies are small and the government's support for them is virtually nonexistent. So it is impossible for BTC to kill banks, which in my opinion is most likely one day that central banks will issue cryptocurrencies.
But the adoption will certainly grow and that will force the government to regulate crypto.
We might not be able the present financial system but with crypto I adoption I am pretty sure there's a major changes that will benefit the people, not only in a certain county but from country to country as its easier to transact worldwide with crypto.