If you itemize your taxes, investment interest expenses (such as margin loans) are deductible against your net taxable investment income, with carry forward of unused amounts. So it nets out to zero.

Margin loans don't give you cash to go buy a car or house, or pay for a fancy vacation. If somebody figured out how to do this they probably are breaking the law. There are also a lot of limitations to how much can be detected in this manner.

So back to the point, at some point, you are going to want to convert your wealth into actual cash to spend. When this happens taxes are levied. Yes at different rates.

Loans backed by your assets do come at lower interest rates, because of less risk, but the interest as profit on the bank is taxed as income -- for the bank.

Also, on the title "U.S. businesses contribute the smallest share of federal taxes" while may fair, looks interesting next to "U.S. businesses pay us nearly all of their paycheck".

I think it would be more simple of businesses had 100% the tax burden, but I don't think it would translate into any of us taking home more cash. All that would happen is wages would lower and businesses would pay the tax.