My motto when recruiting faculty has always been to “find someone better than me.” Granted, there are those who consider this to be a farcically low hurdle, but the principle is valid in any event. One interesting theoretical justification for a tenure at colleges and universities is that it reduces the incentive to hire people who make you look good by comparison, rather than hire the best possible people. This is important because if I’m successful at implementing my motto, then the long run outcome is that I’m the worst person around. Without the protection of tenure, the argument goes, I might be worried about my job security if I’m the worst person around. As the verse points out, the long run best interest of the department and institution is to have wise people rather than fools around, so it is important to create the correct incentives to populate the faculty with wise people.
The other interesting aphorism on this topic is “A people hire A people, B people hire C people.” I’ve heard two reasons for this outcome. First, only the A people don’t feel threatened by other A people. Second, the B people are unable to recognize true ability, and wind up with the least common denominator as a result.