It's not the "people with money" leaving. There's equal evidence of people with money staying and people with money leaving.
It's people who use their money to generate more value and employ lots of people that are, consistently, leaving. That means that thousands of jobs for the lower middle class are leaving and going to somewhere with a more favorable business environment.
And that's not good (well, it's good for the other city).
It's easy for people in tech hub cities to think that's never going to change but history shows boom towns going bust repeatedly. Sometimes they come back (Seattle). Sometimes they don't (the whole Rust Belt + Upstate NY).
And once the talent pool from a few large companies moves to another metro, whole industries relocate their offices to chase it.
Are Seattle, the Rust Belt, and upstate NY examples of higher taxes driving wealthy job-creators out? I think they were the opposite: the market moved and then the wealthy people left to follow it.
NYC has always been extremely expensive, and people have largely decided that it's worth the price. I don't see how a little wobble in either direction changes that. Everyone could have already moved to Miami, or Salt Lake City, or even cheaper places if they were actually price-sensitive.
A "little wobble" may not change it more than a "little", but enough "little wobbles" over time become a "big wobble" that may change it in a "big" way. The right question to ask is: what's the elasticity? So far the elasticity of domestic migration to tax increases has been smaller than many expected due to network effects and inertia, but nevertheless if you look at the population growth rates of high tax states like CA and NY and compare it to low tax states like FL and TX, you will definitely see a pattern. Rational people think on the margin. Perhaps only a few people will move if you increase tax rates by 0.1%, but more on average will decide to move than if you hadn't raised taxes - the question really is, how many?
In recent years many large businesses have moved out of Seattle entirely. Some just outside of the city limits to Bellevue and some out of the state completely.
Also I'm someone who did move from NY to Miami during COVID along with maybe 1/3 of my peers (work and social). Not all to Miami but mostly to either the southeast, texas or non-LA socal.