You could mandate that money transfers go through banks and tax the transfers.

Let's see how rich can get richer without transferring their money.

That has the same impact as other, similarly radical solutions. In the best case the rich will just remove as much of their property from the country as possible. They might keep a villa or two, some cars, and some pocket money, but the majority of their income will be out of reach of the taxman.

Or they might just rent everything they need from a local branch of a company and pay a branch in another country, and the two interact via crypto. Or indirectly via remittances as there will be a market for asking low-income people to transfer money on behalf of rich people, as transactions of low-income people would probably not be taxed.

You can also tax where the asset ownership is recorded. Property records, securities records, etc. If it isn’t recorded with a public body where taxes can be assessed, it isn’t recognized. Wealth must exist on the books somewhere.

Yes, there are ways to tax the rich. We aren't doing it because those who decide about such things are the rich.

This assumes that there is only a single country on Earth or that the rich would not be willing to move to a country with lower taxation. Hint: they are already doing that.

right, because what will really improve their business is moving to a country with less and poorer consumers, they could extract money from

also .. what's bad about the rich moving out? you can always print more money to balance out the money they've taken away

and companies and properties that they used to owned are gonna be sold to some new people who are not that rich yet

Cranking up the taxes will just make life more expensive for everyone. And printing more money is a terrible solution to financial problems.

Letting wealth of the rich grow so much faster than the growth of the economy is so much worse, because it means that the rich are increasingly draining poor of their resoruces.

Debasing the currency has the same effect, as it is equivalent to a flat tax, which hits lower income brackets harder than the wealthy.