Taxes

The Roman Empire ran government of the rich, by the rich, and for the rich. Wealthy individuals were required to pay a lot for government positions, in the expectation that they would be more than reimbursed (by bribes, extortion, etc, within reason). It worked remarkably well .

The Roman Empire mostly ignored individual taxes. Entities like cities and provinces were expected to pay decreed amounts, and were free to raise money any way they wanted. If they failed to do so, the legions went in and looted it. That also worked well for hundreds of years .

Modern government is more “enlightened”. It is run “for the people” meaning, by definition, the poor. It is paid for by multiple … well, the problem is that it really is not paid for. The wealthy, as always, have ways to protect their wealth. Their bribes go to preventing taxation, sometimes by illegal evasion, more often by legal maneuvers like “exemptions” or “investment”. The result is increasingly government by debt

In an age when everything will be made by machine and billions of humans helplessly consume, all bets are off. The very idea of paying for scarce items may be obsolete. 

But, of course, that land of cockaigne remains ever over the hill, far away, and in the future .