Nearly every single one has quietly crawled their way back into those respective cities. Agglomeration effects baby!
Listen, I am sure there is some level of taxation at which the rich will in fact decamp and go somewhere else, but empirically we are nowhere near it, nor does it appear that any of the mainstream proposals (either for increased high-bracket tax rates or wealth taxes) get anywhere near it.
For example, MA instituted a 4% surtax on all incomes over $1M and... and the population of payers actually increased 25% since instituting it[1].
[1] https://www.wbur.org/news/2025/04/28/massachusetts-millionai...