sir1963:
Wealth does not mean income , we tax income.
Capital gains is not income, no matter how much you want it to be so.
If I own a billion dollars worth of property, take out a loan of $100M against it and spend that money on hookers & blow while rent on the property pays back the $100M, that should be considered income. Right now you pay bugger all tax on it because the rent is just paying back a loan, so there is no profit.
If you can use it as leverage to buy more stuff with, you should pay tax on it as if it was income. The concept of income as we know it is nothing more than a sentence in the tax code. It isn't General Relativity. We can change it whenever we want.
I pay tax on goods and services I buy. But that's not income. So why do I pay tax on it? Because we made a law that says I have to.