Go look at my example (post 199) again. In that example, the widget formerly cost $125. Now Persons A & B are paying $100 for it plus $25 in tax. But Person A has already also paid $25 income tax on his money and Person B has not.
Get a grip. You are quibbling..
No tax scheme is perfect, but this one could work.
I read your example in 199 but didn't follow it. Could you try again? I want to understand your point...