Rich people always borrow money on the stocks they own. In effect, those unrealized gains help them borrow money which they spend like income. I will spend part of my paycheck to buy a cup of coffee and they will spend part of the loaned money to buy the same cup of coffee. They can also buy a house with that money. All they need to do is keep paying the 4-5% interest rate on that loan meanwhile the underlying stock appreciates at 15-20%.
Is this a loophole that rich people enjoy? Absolutely. Does this loophole need to be closed - absolutely.