Well, yeah. If you don't realize the gain it isn't taxable income. But literally hundreds of thousands (perhaps millions) of people in the US get stock allocations or stock options. In your post I was quoting:
Mere mortals get stock options and stock allocations as compensation (even administrative assistants at some companies, like Amazon), defer taxation until they're sold or exercised, and take out home equity loans. And even for capital gains, "mere mortals" have lower tax rates than those defined as "ultra-wealthy people". (Last I looked, the financial industry still defined "ultra high net worth" individuals or married couples as those with $30 million of investible assets or more. Still true?)
And home equity loans are exactly the same type of instrument as financially astute people use when getting low-interest loans on their equity holdings from their brokerage firms. I know several people who take out brokerage loans routinely, and invest the loan proceeds in more financial instruments to multiply the return from their original capital investment. I'm too much of a coward to use that strategy, but I know several people who do. (I also know people who sky dive, like helicopter skiing, bungee jumping off tall buildings (my son did that once that I know of), and paragliding, but I prefer boredom to scaring myself to death.)