The ability for an individual to choose their favored tax jurisdiction is an artifact of law, and laws can be changed. If America decides to clamp down on the 1%, it can also create laws to disincentivize leaving for tax reasons, like Saverin did.
Given the condition of the lowest of our nation, "traitors" isn't an unreasonable way to describe the 1%, and no one in the 1% has ever seen a firing squad or the electric chair. Not even lethal injection. If they aren't subject to the same rules as Americans, are they really Americans? If they have a higher amount of wealth than sovereign countries, can they be considered anything but sovereign?
Lots more killing of non-German citizens, of course...
[1] https://en.wikipedia.org/wiki/German_casualties_in_World_War...