This is a simple case of laziness by Econ prof. He throws out the rich people are leaving because a few high profile billionaires like Elon musk, and some Hollywood types stomped their feet on the way out. But of course the data like that you provided paints a very different story. He likes to throw around threats of data, but he has none to prove his case. All he has is his lazy rhetoric based on his political footstomping
