<p>Here is another way to look at tenure: it pushes young scholars to be inventive and productive during the early stages of their careers, a time when most have their most original ideas that they can later build upon. While some professors will indeed slack off later, having exhausted their ideas, others will continue to publish/research. Those without research will teach more than their more productive colleagues, thereby allowing the active researchers to teach less. These tenured teachers have more experience and knowledge than the junior faculty and can be valuable assets to the department. </p>
<p>Tenure is not free job security. It is given because the university wants to keep the individual for many years.</p>