While I respect your schooling.
I don't care if you are Austan Goolsbee. I would not completely agree with him, if he made your statements either.
The curves represent far more than you claimed.
Yes, in some places they show what you say.
But there are other locations on the curve to examine.
Just go to the ends of the curves and think about it.
100 percent tax of nothing is less revenue than 90 percent of some profit/income.
on the other side
10% of something will be more than 0 percent.
b. Laffer did not create the concepts in any way shape or form. The concepts are basic to economic theory.
As I said the question is, where we are on the curve. Not, that the curves exist.
c. For instance... Keynes himself taught the concept...
"When, on the contrary, I show, a little elaborately, as in the ensuing chapter, that to create wealth will increase the national income and that a large proportion of any increase in the national income will accrue to an Exchequer, amongst whose largest outgoings is the payment of incomes to those who are unemployed and whose receipts are a proportion of the incomes of those who are occupied...
Nor should the argument seem strange that taxation may be so high as to defeat its object, and that, given sufficient time to gather the fruits, a reduction of taxation will run a better chance than an increase of balancing the budget. For to take the opposite view today is to resemble a manufacturer who, running at a loss, decides to raise his price, and when his declining sales increase the loss, wrapping himself in the rectitude of plain arithmetic, decides that prudence requires him to raise the price still more--and who, when at last his account is balanced with nought on both sides, is still found righteously declaring that it would have been the act of a gambler to reduce the price when you were already making a loss."