The primary issue with this is the way shares and equity work. Elon Musk is a trillionaire on paper. He pays himself famously little.

That net worth is, under our current system, tightly linked with his interest and control in his various enterprises.

He can borrow against it which gets around taxes and that should probably be addressed, but he like the hypothetical fresh billionaire startup founder don’t have that money. And the mega rich on paper can’t access more than a small percentage of that money without reducing their control of the company they built or are building.

Ideas like a wealth tax, or the new sovereign fund paid into by an equities tax or grant are all interesting, but they are all more complicated on the ground than “wouldn’t $100m be motivating enough?”

FWIW, I think that some sort of public endowment and/or sponsored healthcare, education and safety net and/or tax or management of hyper wealth is one of the problems of our age.

But part of that problem is that it’s not clear how to do that in a way that is workable in an increasingly multipolar world of tech and soon healthcare giants that are as powerful as small but growing nation states. Economically and in some cases militarily linked to great powers.

Just don't step-up cost basis at death and you solve the problem. Elon's fine, we can wait until he dies and his heirs sell their shares.

Who is it that implements the rights around ownership? Who is it that will (possibly literally) go to war to defend this right? Maybe he should pay a bit of tax on this right since he expects others to defend it.