Try Gavin Wright. And Roger Ransom.
Using Time on the Cross undermines your credibility. Times change.
Wrong again. The Fogel quote isn't from Time on the Cross, and in any event much of Time on the Cross has been confirmed.
For example, Wright actually confirms Fogel's findings on the profitability of slavery.
See Gavin Wright, “The Political Economy of the Cotton South,” in Gavin Wright, Households, Markets, and Wealth in the Nineteenth Century, 1978, W. W. Norton & Co. It’s reprinted as a chapter of Michael Perman’s The Coming of the American Civil War, Third Edition, titled “The Economics of Cotton, Slavery, and the Civil War.”
Wright refers to an analysis by Yasuhichi Yauba and Richard Sutch in which “in each year the price of slaves is determined by the interaction of a demand curve with an inelastic supply curve, because, after the closing of the African slave trade, the aggregate slave labor supply could not be increased in response to higher prices, except over time. The observed slave price was in fact well above the long-run cost of rearing new slaves, and the difference between the two accrued as a capitalized rent to the owner of the slave at the time of birth. Slave prices rose steadily over time, to levels far above the rearing cost, and indeed were never higher than on the eve of the Civil War.
“The point is not just that the real proof of profitability is the high slave prices themselves, but that the rising profitability is embodied in the higher prices. In the abstract, there is little point in sharply differentiating between the slaveholders’ interest in annual earnings on his crops and in the value of his slave property, because slave prices will reflect the expected stream of future earnings from the use of slave labor. . . . The fact is that virtually every slaveholder who was careful enough to keep his slaves alive made at least a normal profit during the 1850s from capital gains alone.” [Wright in Perman, pp. 160-161] According to Wright, “the essence of the profitability of slavery was the financial value of slave property.” [Ibid., p. 162]
As to the Fogel quote, he's referring to the real price of cotton, which is the price of cotton when the effect of inflation is removed.
As this study shows, "since the Civil War, cotton volatility has largely coincided with broader commodity price volatility."
Ransom, for one, considers the nominal value of cotton, not its real value. "The real economic failure of the postwar South was the unwillingness or inability of farmers to adjust to changing agricultural markets." [Roger L. Ransom, Conflict and Compromise: The Political Economy of Slavery, Emancipation, and the American Civil War, p. 242] Ransom shows a postwar depression in nominal prices after inflation during the Civil War. See page 258.
So you're using Wright's and Ransom's apples to criticize Fogel's oranges.