If I understand you correctly, you mean that wealthy americans who have built their fortune and life in america will choose to not only leave but also revoke their citizenship and leave the US? All because they have to pay more money than before in taxes?
Personally, I don't think all millionares and billionares are willing to leave their life and family behind because of a some dollars in federal tax...
Personally, I don't think all millionares and billionares are willing to leave their life and family behind because of a some dollars in federal tax...