Separation of powers is easy to erode and we are seeing that happening in a lot of western countries. Companies are, of course, never going to be trustworthy, but they at least can go out of business if they go full dystopian.
This reminds me of how all the drug dealers use USPS because it actually requires a warrant to open the package.
If the government has to enforce banking KYC/AML itself they won't be able to hide behind all the third party fuck-fuck games and they'll get sued into oblivion. I'm sure they'll play the normal federal court and sovereign fuck-fuck games but it would be glorious trying to watch them try to enforce the BSA and Patriot act bullshit while not being able to hide behind the auspice it's just a private bank collecting the data.
Yes, I'm aware someone is trying to undermine it in the U.S. currently. That doesn't mean that companies are a safe haven suddenly.