About 170 million people residing in America already pay zero income taxes. And a majority of the voters like it that way. Don't worry; Fedzilla will eventually go hunting down the clever expats that got away, which means more Demonrats on the roll to collect money for Demonrats on the dole.
You miss the point. If the USA collapses then so will the money going to expats from defunct USA banks and businesses.
I have to laugh at expats that speak of how their retirements and social security goes farther in other lands as they don’t consider how precarious their situations are should the USA itself fall and social security goes away.