Its pretty hard to flee the States to shelter income. The U.S. gets you whether you live here or not once you are over your Foreign Earned Income Exclusion (I don’t think there is an unearned income exclusion) - and if you are going to stop paying taxes you have to decide never to enter the country again or risk getting arrested for tax evasion. For unearned income, taxes on qualified dividends and LCGT have been so low in the U.S. that I doubt it would be ample incentive to flee.