Galbraith saw most advertising as wasteful and manipulative. Marginal Revolutions and Brad Delong discuss whether Gary Becker "proved" otherwise, but it's really Lee Benham seminal empirical work that's relevant here. Contrary to the monopoly explanation of Galbraith, advertising often lowers prices. Benham documented that prices of eyeglasses were significantly higher in states banning advertising than in those that did not.

Galbraith thought market power allowed firms to set prices and preferences. The outperformance of small stocks relative to large stocks (the small stock effect in the Fama-French 3 factor model), suggests he had it backwards. As he expounded this market power theory in his popular book The New Industrial State in 1967, he top-ticked the large conglomerates with that thesis.

Galbraith argued in The Great Crash that the Great Depression was caused by reckless speculation during the 1920's that led to a financial crash. Friedman and Schwartz, as well as Bernanke and the current Federal Reserve, believe that the Fed needlessly shrank reserves and turned a minor recession into a Great Depression.

Everyone agrees he was a good writer, meaning he used big words, imaginative metaphors, spoke with supreme self-confidence, and wrote best sellers. He often castigated "conventional wisdom", yet by promoting the standard Keynesian diagnoses and remedies of the post WWII era epitomized conventional wisdom, especially as a best-selling economist (you have to admire the chutzpa of a best-seller writer damning popular ideas).

During his life he was considered an intellectual peer and rival to contemporaries such as Friedman, Hayek, Solow, and Stigler. But unlike these latter names whose work is still studied by graduate students, his name doesn't show up in any of the indices for my graduate level micro, macro or finance textbooks, his supposed areas of expertise. He prided himself of writing directly to the public because he could, noting once that he had never had a journal submission rejected because he wrote books and articles for non-refereed magazines. I think nothing is more dangerous to one's ideas than becoming able to work without and editor, or referee, of some type.

He seemed a good man, in that he was honest and well-intentioned, and here I'm sure he has left a fine legacy for his friends and family. But his legacy to economics, is virtually non-existant. Big firms are generally weak, advertizing increases competition, depressions are not caused by excessive speculation, and conventional wisdom has always been for greater government regulation and redistribution.