Cryptocurrency has grown. Just think between 2009 and now Crypto has taken over almost all the sectors of the world global system. Cryptocurrency and traditional system are two different financial system with different ides. Tradition bank can develop chain to integrate the traditional institution to comprehend with blockchain idea since everyone is now in for digital currency.
Yes this can be easily done. But guess what there is an obstruction in between. And that is the government.
Due to the decentralised nature of the Bitcoins, it cannot be controlled by the government, and therefore government is playing the major role to prevent Bitcoins to get accepted globally.
As Bitcoins are cannot be controlled by the government, therefore they are unable to impose tax on it. And also for that reason, they have instructed all the traditional banks to not pair with any cryptos.
And the traditional banks are majorly funded by government, so they are abide by all the rules that the government will give them.