If you read Feynman's nobel acceptance speech (https://www.nobelprize.org/prizes/physics/1965/feynman/lectu...) and some of the other interviews he gave about his QED work, you get the sense that his model of working was to listen carefully to what other people in the field were asserting and then devising a method for proving (or disproving) to himself with his own calculus driven methodology. He got really really good at it, and it lead him to understand the whole field of study better than anyone else. I can see how it could lead to the crisis described in the article, because he would have to spend less time analyzing the work of predecessors and more time pursuing, and then testing, his own hypotheses.