> It's well known that despite the high marginal tax rates of the past, very few people ever paid those. Deductions abound that have since been eliminated.

I read the article, in which this expected point is addressed. From TFA:

>They have constructed a historical database that tracks the tax payments of households at different points along the income spectrum going back to 1913, when the federal income tax began.

That is actual payments, not whatever the tax law says should be paid. Did you think academic economists wouldn't address this point?