US citizens are taxed on world-wide income, so the benefits of the low-tax environment aren't so much of a factor, since you owe the IRS on whatever you earn anywhere on earth (but for a ~$80k exemption).

Most other countries tax based on where you earn (i.e. earn money while resident abroad => don't have to remit tax on those earnings to your birth-country).

AFAIK, Sivers (smartly) had a lot of his exit proceeds put in a trust, so he may be somewhat tax-agnostic.