Governments don't want it and they wish they could prevent it, because they cannot track you easily, they cannot tax you, they ..., they ..., they...
Governments like censorship, and there is 0% censorship on bitcoin.
The reason is that they are not getting benefits from cryptocurrency transactions. They can't collect taxes because it is centralized and its anonymity will really make them struggle on finding those transactions. Taxes from bitcoins are really the urge of some governments that's why they are legalizing it, but not all countries have that knowledge about bitcoin.
Mass adoption isn't enough. Governments must agree with the idea too. In fiat, if the central bank gets hacked, insurance will just make a case to get your money back.
In bitcoin, there's no such thing like that. The government is not responsible with your money or assets, they are not the one who will give back all of those losses once the bank gets hacked.
Cash is more often used in money laundering and do you think that cash isn't even used for illegal activities? It's even the most used currency for those methods and this taboo about bitcoin must be changed.
Fiat money is the most used currency in crimes or scams, especially that not all people are knowledgeable about the existence of bitcoin and other coins.
Some people only recognize fiat money and not cryptocurrency that is so complex and technical to hold.