The News and Observer hit the nail on the head: legislators pay their own employees longevity pay because they value their expertise; the expertise of veteran teachers is discounted.
Here is the story, written by Dan Kane, as good a reporter as I have ever met:
NC Teachers Lose Bonus Pay, But Others Still Cash In
Their photographer, Harry Lynch, let me talk for a while on this video:
There is no magic to good schools. Put good teachers in classrooms and give them support; help families help their children. It is pretty simple, and it is pretty hard to do. Experienced teachers are going to be better teachers than new teachers, and experienced teachers are the ones who help new teachers become good teachers. Also simple, and also ignored.