As you are no doubt aware, this is just a variant of the basic principle that when selling a product there is a price that maximizes net profit.
Lowering price will generally increase number of units sold, but will by definition reduce profit per unit. At some point, one begins losing money on each unit sold. No, at that point you cannot make it back in volume!
OTOH, raising the price always increases the profit per unit, but normally will decrease the number of units sold.
In a monopoly system, which of course taxation is, there is always a specific point where these two factor balance out and the greatest total profit (or tax revenue) is generated.
One can argue about where that point is, but I find it really difficult to imagine anyone could seriously contend the point doesn’t exist.
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You mean the Leftists won't dispute it ?