re: The Laffer Curve turns 40: the legacy of a controversial idea

Yeah.

The over simplicity isn't in the shape of the curve so much as it is in the number of variables it depends on. Obviously government revenue depends on a lot more than just the tax rate (not to mention just the tax rate itself is more complicated than a single number), so the Laffer curve itself is subject to change where its peak is and alter its shape a bit depending on other variables.

It also ignores changes in government spending that might result from tax rates. A regressive system, for instance, tends to result in more government subsidies to the poor than a progressive system.