Many people have to pay tax on their income before they use it too. Why should the person sitting on a fat investment portfolio not have to? Can I borrow again

Many people have to pay tax on their income before they use it too. Why should the person sitting on a fat investment portfolio not have to? Can I borrow against these unrealized gains you say make no sense to tax and still spend the money, but perhaps never pay taxes on the gains ever?? If instead of taking income I take a carried interest in my portfolio can I defer taxes - maybe forever? By the way, all these are the loopholes that are CURRENTLY being used by the well off to avoid paying taxes. Seriously - why do you think portfolio lines of credit are so popular?