Nor, I contend, is it necessary to publish early and often to be a good philosopher who has an important contribution to make. As an undergraduate I was incredibly fortunate to be taught by very good philosophers who thought a great deal, published little, and devoted a great deal of time to exploring philosophy with their students. Back then, people only published if they had something to say—and the advancement of their careers depended, not on the length of their CVs, but on their reputation and the quality of their minds. Not publishing early is not a hindrance to having a productive publishing record later. Jonathan Dancy published little for nearly a decade, and Donald Davidson was another late starter. Neither would have flourished under the present tenure system.
Publication is, in fact, a poor metric of quality when we are talking about philosophy; setting aside truly stellar papers, which are a miniscule portion of those written, its primary value is simply as an indicator of active participation in philosophical inquiry. It does have the advantage of being an indicator that's fairly easy to trace. But there are many other ways of actively participating in such inquiry.