>>The analogy is specifically for tax-cuts. <<
It's a poor analogy because income tax is not based on the cost of things purchased. It's a trivial, contrived story that pretends there are just as many people in the $59 tax bracket as in the $18 bracket with nobody in between. If you already believe that theory, you might say this is clever. But it is not clever enough to convince anyone who thinks otherwise, so it is really pretty useless.