Trump now has this fantasy of using tariffs to try to force companies to come back to manufacturing in the US, and he’s destroying the economy to try and achieve it.
The US economy is being destroyed because of the incompetent way that tariffs have been enacted with no notice, no planning and no logic.
A competent government would have announced tariffs years ahead of when they would be implemented and the % would slowly increment to the maximum level. That would actually give companies time to setup manufacturing in the country. And there would be certainty the tariffs were actually going to exist.
With Trump you have no idea if tomorrow tariffs will be 800% or 0%. So what is the point of moving manufacturing to the US, you may as well just bribe him and sit by his side massaging his moronic ego so he does you a favour.
The only way to prevent that is to impose draconian measures such as restricting freedom of movement and capital controls.
Measures do not need to be draconian. When wealthy individuals move away they're typically just defining their primary residence as being elsewhere. They continue to own properties and luxury goods in the country. It would be trivial to impose taxes on those. In many cases the individual will continue to spend most of their time in their original country. Relaxed restrictions on non-domicile status permit this and it could be easily remedied.
That's incredibly dramatic and simply unfounded.
Taxing capital gains is fairly standard worldwide. You aren't taxing people for holding investments you tax them on the profit they make from them.
All you're describing is loop hole after loop hole all of which can be easily contained. This one in particular is extraordinarily specific and I highly doubt it wouldn't already be covered by rules in a developed country.