It’s an interesting and hard problem. Because most billionaires don’t own billions in cash - they own companies that are worth billions. These companies also don’t have billions of assets - they are valued at billions by investors.
The problem is that musks and bezoses of the world didn’t start with billions - they started with millions and lucked out. So to prevent this from happening you need some system that can fairly catch a moment where a business becomes too big and do something about it.
You can’t really cut the majority owner out, because well they own the company - you can’t just take away what they own. But you can’t really pay them some ceiling cost either - you’ll just end up making someone else a billionaire.
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