I think if you saw a headline claiming "The millionaires have left New York" you'd spit out your drink.
Sure, some millionaires have left, but not nearly enough to call it an exodus - "the millionaires" as a class are still there; they never left.
Indeed, according to Forbes, there are more billionaires living in NYC than any other city in the world: https://www.forbes.com/sites/giacomotognini/2020/04/07/world... And according to this cnbc article, the same is true for millionaires: https://www.cnbc.com/2019/01/18/new-york-city-has-more-milli...
Saying that some still remain doesn't refute my statement.