Good luck moving your entire business, real estate and other fixed assets abroad very quickly. Have fun paying all those exit taxes. Because those already exist in a lot of places.

Companies could be moved pretty quickly, and once you move the company headquarter, most of the job is done, the business don't need to move, simply the money generated goes somewhere else. Real problem could be the real estate, but that is solvable.
Personal wealth ? Movable without too much trouble.
It not quick in every aspect but it is doable.

And that all is implying you want to leave over a wealth tax in the first place because something tells me you won‘t.

I think this depend on where you live.
In Norway probably you are right but we had other examples where rising tax on the rich ended with the rich fleeing the country. In EU there are countries that are "at war" over the retirees, trying to offer better taxation to attract them (basically because they know that even if they pay less taxes, living there they spend money anyway), so maybe it is not completely false that people would go where the taxes are lower.