Cryptocurrency companies won't be able to easily overthrow banks. Banks have an established, interconnected system across the world, and it's never easy to displace them in the near term. However, I hope they can do so in the long term..
Currently, I see almost the opposite: governments that support banks are seeking to contain cryptocurrencies by merging them with banks. This merger, as it stands, is not in the best interest of the crypto community, as it poses a significant risk to decentralization and privacy.