Since there has been tax introduced for crypto, why couldn't the government do it for crypto as well?
Most crypto I am aware of is as public as can be, if you were forced to verify your identity then they could directly track your transactions as well. And any somewhat anonymous crypto could just be made illegal, you could theoretically still use it, but you'd still have a log that says you got money from nowhere, which I think could warrant an audit if done a lot.
Actually, by many accounts, Tether (USDT) has been based on some kind of fractional reserve (nobody can prove that or disprove that), and USDT happens to be the top (?) stablecoin in use.
But cryptocurrency doesn't fix this, it just pretends to by throwing everything out of the window. I think what would ultimately work is a global 'bank' that implements all the safeguards the current system has without governments being able to touch them. That means it has to work within their legal frameworks, but also have high integrity and security to avoid the corruption... Which is probably fanciful, much like the idea crypto will fix it.
The other major class of banking regulation has to do with governments monitoring transfers of money. I'm not entirely convinced a weakening of their ability to do so would be a bad thing.