To answer Orin's query below, there aren't many scholars who have argued that Lochner was correctly decided, but there are some, including not just Siegan, but the VC's own Randy Barnett, Richard Epstein, Ellen Frankel Paul, Roger Pilon, among others. There are a number of other scholars who are generally sympathetic with Lochnerian cases, but haven't endorsed the particular holding of Lochner, including Alan Meese, Michael Phillips, and Chris Wonnell. Yet another group of scholars argue that the Court went too far in the Lochner era, but that the Court then went too far in the opposite direction in completely refusing to protect economic liberty. Walter Dellinger, Rebecca Brown, David Strauss, among others, fall into this category. A fourth group, including Bruce Ackerman and Owen Fiss, seems to think that Lochner was correct for its time, but properly didn't survive the New Deal Reformation.
Meanwhile, revisionist legal historians including myself, G. Edward White, Barry Cushman, and Howard Gillman have spent the last couple of decades placing Lochner and its progeny in historical context, destroying the myth that Lochner was a "Social Darwinist" opinion issued by a Court seeking to favor corporate power over the rights of workers, and showing that the Court's reasoning was consonant with American political and judicial tradition. Meanwhile, Justice Holmes, author of a famous pithy dissent in Lochner, has seen his reputation plummet.
Contrast the above with the virtually universal condemnation of Plessy or Dred Scott, and one can see that Lochner is no longer in the same anti-canonical league as those opinions. And contrast the above with the way Lochner and its progeny were universally condemned a couple of decades ago, to the extent that after a reasonably exhaustive search I could find only one law review article published between 1937 and 1980 (the year Siegan's book was published) even mildly praising "economic substantive due process." All in all, Lochner is losing its anti-canonical status, and Siegan is as responsible as anyone.