Something that has been unclear to me is how will governments survive when fiat is nowhere to be seen and all or most monetary transactions happen via cryptocurrencies.
Government will be government there are so many ways for them to survive. They had the power to do anything they want, they can disable crypto transactions or make their own cryptocurrency and force their citizens to use it. This is how the government works, everything is possible to them even people loves decentralization.
Since one of the most attractive aspects of crypto is that its anonymous and decentralized, how will governments be able to keep track of money and tax it.
Registration of exchanges and by requiring users to send their verification through ID's and this is what's happening now. They can tax the exchange and if possible soon they'll track those crypto users who are earning with it and avoiding tax, everything is possible to them.