They treat Florida residency like a flag of convenience[1]. There are some who legitimately retire or move to Florida for a lifestyle change - not exactly a new phenomenon - and a bunch of young professionals who choose to live in Miami because it's Miami, but for most it's just paperwork.
David Tepper is a great example. He "lives" in Florida and moved Appaloosa to Miami, but Charlotte is now the center of his personal life and he spends almost half of his time there.
Saying that some still remain doesn't refute my statement.
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...
NYC has the highest concentration of millionaires in the world.