You need to go back to school professor. All wealth tax proposals are progressive, only affecting those with substantial investments. I used to dislike them, but a tax starting at 1% on $50 million with the highest rate (say 3%) on net worth above $1 billion wouldn’t hurt anyone.
Also, that tax can’t be avoided either. Even if a billionaire moves to a tropical island with no taxes, their money is still invested in developed countries. It’s too much to invest in tax havens. You just need good KYC to know who the ultimate owner is.