I grant you that BTC is harder to outright take/confiscate/steal as a bank account or a bar of gold but most people are employed in some way by companies who operate on the government's turf - and the government expect their cut, so they'd pressure those companies to reveal how many sats they give you just like they do with dollars and pounds right now, and the people coming to collect shoot to kill if necessary.

And about fleeing, I really wish it would be the case that people would actually "vote with their feet" in massive numbers but most people are bound by family, culture, or language to the area they live in so unless circumstances become unbearable (see perhaps California) or countries become way smaller (the South tried that, see how that treated them), the local government will always have massive power over those unwilling to cut and run, and enhanced wealth preservation with BTC, while solving a great deal of problems in many areas, would likely do very little to rectify that.

Please don't get me wrong, I'm arguing these points out of something like academic interest and to warn people that their well-laid plans might well be thwarted by the government but always in the hope that people come up with ways to affect lasting, unstoppable, positive change.