When your job pays you a dollar, you get an actual dollar. Your job never claws that money back. Unrealized capital gains are not money, and they routinely get clawed back. Unrealized capital gains just means someone in New York traded GOOG/GOOGL at a higher price than they did yesterday.

And, sure, super-rich people can in theory use the appreciated stock as collateral for loans and not pay taxes, but in practice Larry and most other centi-billionaires actually sell loads of stock and pay a lot in capital gains taxes because having your status as super rich dude who owns a huge yacht be totally dependent on Google's stock price is a dumb risk to take on, and it's worth paying some taxes to eliminate that risk.