Let's play the rich get everything. The rules are the rich get everything. participation is mandatory.
Did I say mandatory? I meant optional! You're "free" to die in a cardboard box under a freeway as a market capitalist scarecrow warning to the other ants so they keep showing up to make us more!
You absolutely can have unrealized gains without a stock market. Build a business. Someone wants to buy it from you for $150,000 this year, someone else wants to buy it from you for $250,000 next year, you have unrealized gains of $100,000 from last year to this year.
What we can do is apply an annual wealth tax of 1% of all registered securities, (stocks, bonds, etc) and exempt the first $10 million of each natural person. You don't have to sell your shares; the SEC knows how much you're holding, and will transfer them automatically to IRS liquidators, who will resell them on the open market in small lots, no more than 1% of total traded volume per month.
Jeff Bezos and Elon Musk lose 1% of their empires per year until they are worth less than $10 million.
There's your problem. Business shouldn't be bought and sold either.
What we can do is apply an annual wealth tax of 1% of all registered securities, (stocks, bonds, etc) and exempt the first $10 million of each natural person.
That's not my preferred solution, but I'd take it over nothing.