Because the media likes to define the QBs in the most basic terms.  If you judged Elway or Manning by their first season you would say they are a bust.  They had terrible first seasons.  I think Trevor is going to continue to improve and be the guy.  He took too many hits last year and his health suffered but he is firing the ball quick this year and is on point with his reads and accuracy.  He is going to put up some numbers once he gets in the rhythm of the new offense.  Something he can't do as effectively if he is looking over his shoulder all the time wondering when they will name the starter.