[mikestew]

Because there's no "simply" about it. Go ahead, mentally walk yourself through how that plays out for the rich person. Please account for all assets and potential tax liabilities. Factor in the means of production for the rich person to stay rich, and what happens when that person is no longer a U. S. citizen. All done? Oh, forgot to tell you, there's a dozen other things you didn't even know about, but the country of your previously-held citizenship will be along shortly to helpfully remind you.

That, and where else are you going to go that is more "business-focused"? Suppose you find such a place; what trade-offs are made to live there?