The thing that Bill does not get--but you implied it in your own statement is that Priesthood is a vocation, not a career path.  For Protestants, ministry is what they do, but it is not necessarily who they are. For Catholics, priesthood is who they are, not just what they do.

So a priest might be a pastor--that is his particular assignment at the time--his "job" if you will.  But priesthood is who he is.  He will never cease being a priest, not even in heaven.