Most of these billionaires are founders of companies that were worth many billions of dollars before they ever turned a profit. There is no option just to pay out the cash to cover the gains tax.
I don't really see a problem. There would just be a new equilibrium. Pay salary->increased burn->lower valuation. The valuations are mostly detached from reality currently, it would bring it more in line.
And the Income Tax originally was only 3% and only applied to less than 1% of the population.
The idea that it would apply to everyone, and be 20% was literally laughed out of the debate on implementing a national income tax as a "crazy conspiracy", it took less than 50 years before that crazy conspiracy was reality.
There is little reason to believe history will not play out the same, and it will not be long before this expands beyond the evil billionaires you despise soo much to those mom and pop stores you seem to claim love for...
Walmart didn't go from mom and pop store to national corporation without an IPO.
I'm going by wiki data here, which says they had 18 stores and annual revenue of 9 million in 1968. If they had stayed private they were probably clearing a million dollars a year, give or take. To get from there to billions they had to raise outside money, specifically by selling stock and debt to someone else. That is by definition "not owning it anymore" because they're selling (some of) it to raise funding.
Like I said, there are no mom and pop billionaires. To get from millionaire to billionaire requires outside money. And yes, that includes tech companies. I know tech founders like to write false hagiographies for themselves after the fact about starting XYZ in a garage, but dig far enough and you usually find it was more like "garage + 25 million from Sequoia Capital," like Google.
