Compensation principles, as well as guidelines for reward and recognition systems, call for remuneration to be based on perceived market value for any given job.  Generally speaking, therefore, we can conclude that the public does not value the role of the teacher very much.  The pay is fairly low relative to the preparation required, the time spent on the job before, during, and after school, and the paltry raises given based on performance.  All that plus the constant criticism teachers receive from the far, hard right wing extremists.