The poorest billionaire in California will make about $300 million this year. If we pass the CA wealth tax, he will only make $235 million. In exchange, millions of the poorest Californians will get health insurance. That's the tradeoff billionaires are not willing to make.
The issue is they consider something like this to be an "opening the flood gates" scenario.
Which of course is bullshit since they don't actually pay taxes. At all.
This isn't an opening of the floodgates to more taxes for the hyperwealthy this is compliance enforcement for being part of society.