What is the advantage of becoming a full professor if you already have tenure as an associate professor? What is the advantage of becoming a full professor if you are already an associate professor with tenure? Why not just stay an associate professor for life? What is the key difference between an associate professor and a full professor?

Why continue to write papers if you already have tenure? Can't a tenured associate professor stop writing papers and still have a job?
Why continue to write papers if you already have tenure? Can't a tenured associate professor not write papers and still have a job?


The general answer is simple: most of the people who would quit doing research after tenure in fact quit before tenure.  The ones who make it to tenure generally care about research and intend to continue at it for a long time. 

In more detail:

Reaching an associate professor position in a research university is a long journey.  At this stage you could stop writing papers and lead a comfortable life, if you were willing to live with the disapproval of your department chair (which is not an easy thing: there are many ways they can make your life unpleasant even if they can't fire you).  However, if that's all you wanted, you could have had it with much less effort along the way.  By the time you reach tenure, you have let many opportunities to change your career go by, and you have repeatedly passed through filters intended to measure your talent and ambition.  This selection process means tenured professors at research universities generally really want to do research.  Now, sometimes people change their minds or burn out, and a few might never have intended to maintain their research programs.  However, on the whole this is a group that has been selected for research enthusiasm and ambition, so it's no surprise that on average they maintain the desire to do research.