Those billionaires don’t sell their shares but they do take extremely low interest loans that are non-taxed against those shares kicking their tax obligations into future generations while using liquidity to live as if they’ve sold the shares.

So I’d suggest the tax code be amended to account for that.

That's also a reasonable suggestion. It wouldn't stop them from becoming billionaires. The GP suggested "every billionaire is a policy failure". What's the policy success that prevents this failure?

"No one is allowed to start a company by themselves"?

"No one is allowed to join a startup unless they get more than X% equity"?

"Startup founders must give more than X% equity to their first N employees and/or investors"?

"Bootstrapped startups are not allowed"?

"Once a startup becomes more successful than X, the founder must sell"?

But eventually the tax liability is paid. If after death, they get hit with the estate tax which is even worse than just eating the income tax.

Taking out loans defers tax. It does not avoid or lower it.

Ah but you see, once you are ready for your estate to take the money you set up a granter retained annuity trust.

So long as you don’t die, and your trust earns more than the IRS theoretical rate you can pass on the money almost tax free. While still getting loans against it.

If you put assets in a GRAT you can't borrow money against it

This is correct; GP mis-typed the income angle. Instead of taking loans as typed, the grantor retains the right to receive an annuity stream over the trust's term.

Right. What I meant is you can get the loans against the balance before putting it into the trust and after the trust itself provides the income.

> At what point would you suggest the government should have taken away that 8% ownership so he would not become a billionaire?

I'm not suggesting that.

It's ok if people are billionaires, if defined by having large holdings that, if liquidated, would shrink to non billionaire scales to give back to society.

It should not be possible for a single person to own 8% of the company the size of Amazon.

If you're starting from scratch, there are many ways to do so. For example, make issuing corporate charters contingent on being employee-owned - so if the company grows, so does the number of owners.

If you're starting with an economy with extreme concentration of capital to begin with, gradually ratcheting up progressive taxation on such concentrated capital seems like a straightforward way to force the owners to spread it around.

Or you can offer substantial tax incentives for founders to cash out by selling to their own employees; e.g., the ESOP system in the US.