Academics typically don't get tenured until the age of 40. This means that from their years as graduate students and then assistant professors, from age 25 through 38 or 39, they have to toe the line. They have to do things in the accepted way that their elders and superiors require. They can't be controversial and all the rest. So tenure is, in fact, the enemy of spontaneity, the enemy of intellectual freedom. We've seen this again and again. And even people who get tenure really don't change. They keep on following the disciplinary mode they've been trained to follow.