What these people will come to terms with is a pretty age-old lesson - there are things more important than just how rich you are, and most of those are human. So long as they can maintain their lifestyle, I think many will want to stay. Needing to find 20K in a couch cushion to pay for your 5M in assets each year that you make 300K on won't be the thing that makes you move.
Of course, the rich today also have many legal shields and layers that will protect them from real french revolution violence. But I think anyone can feel the shift right now. Go on Tiktok and see just how many young people are getting real into eating the rich :)
I think this is probably true once someone has a career and a family, but the college part doesn't pass the sniff test for me. the "just graduated college" group is probably the most mobile slice of the overall population. especially if you chose a college away from your hometown, you are pretty likely to either move back home or pursue a career somewhere else entirely at the end. I think other folks are also more mobile than you give them credit for. unless they currently have children in school, I find people are pretty likely to move if they see an opportunity for a significantly better combo of salary/COL/taxes.
If we're comparing high-tax states, I think NY is better run, and more interesting overall than California. The only think Cali has going for it is tech (relatively unimportant to the super rich), and warm weather.
https://www.seattletimes.com/business/rich-americans-increas...
https://variety.com/2020/dirt/moguls/ex-google-ceo-eric-schm...
I know that the uberrich get away with dodging taxes all the time, but there are potentially high costs, like having your assets confiscated, or having to hide out in your island fortress and never return to the US lest you end up in prison.