For the ultra-wealthy, leaving the United States is rarely the preferred strategy; instead, they use their immense resources to legally reshape the tax code and utilize complex loopholes. Billionaires like the Koch and Scaife families historically avoided massive estate and gift taxes by creating "charitable lead trusts" and private foundations. This allowed them to pass fortunes down to their heirs tax-free, provided they donated the interest to charities (which they often controlled) for a set period. A powerful approach is to fund political movements to slash taxes for the top brackets. For example, a coalition of eighteen of the wealthiest US families spent nearly half a billion dollars collectively to successfully lobby for the reduction and eventual repeal of the "death tax" (estate tax), saving themselves an estimated $71 billion.

And, of course, in the ancient world, free citizens of Greece and Rome considered direct taxes tyrannical and usually avoided them, leaving such burdens to conquered populations.

So I guess taxes are uncertain, but only for the oligarchy.