The "Rich" are not really leaving, they are merely relocating to other residences. An issue for NYC will be people working remote from their CT, Westchester, Yacht, Hamptons residences and the city losing that 6% tax. Burt you never know, I moved to the burbs two years ago and still pay that tax, it ends up being a wash for me as I deduct it on my Fed Tax and it's a non issue for me cash flow wise.
There is a huge exodus w.r.t. to upper middle class (which probably 3%'ers to 1%'ers) moving to the 'burbs. real estate sales are up 50-70% in in neighborhoods that are close to NYC commute wise, DIx Hills (an hour by Car/LIRR), CT (places like Westport, Stamford area, etc) Maplewood NJ, Westchester. This is more driven by Covid getting folks to throw in the towel on the city for more space. We pulled the trigger two years ago knowing it was going to happen at some point so why not do it then.