They don't though. Swiss tax wealth (though its a tiny fraction). IRS makes it a massive PITA to hold substantial financial stakes in foreign companies. See FATCA and GILTI. And many tax deferred foreign retirement funds are not treated as being tax deferred by the IRS. It only gets more complicated from here. It's by far easier to earn and hold cash in America.
That was many years ago. The entire Western world is compromised and reports to the IRS -or- the bank kicks out anybody who MIGHT be a US Citizen to avoid being sanctioned. The end result is only the few most central banks in the country take American clients -or- they are hopelessly behind on regulatory compliance (YOLO).
