That statement is obviously drivel. On this though > Also, in parallel, Herb Simon started in the earnest in the 1960's and, a short time later It's actually

That statement is obviously drivel. On this though > Also, in parallel, Herb Simon started in the earnest in the 1960's and, a short time later It's actually worse than you've stated. Herb Simon was working at Carnegie Mellon on bounded rationality and a student of his, John Muth, studied a special, unrealistic case called rational expectations. The topic was basically ignored until the early 1970s when Lucas (working at CMU) familiarized himself with Muth's work. After a great deal of opposition, and some years, rational expectations became the dominant paradigm in macroeconomics. You have to be willfully ignorant to claim economists have always assumed rationality. Simon had his Nobel for his work on bounded rationality long before Lucas got his, and Muth never even got a Nobel.