Teachers with tenure who were not effective, could not be replaced without a prolonged court battle initiated by the union. School boards differ across the country. The teachers in attendance all voted for teachers to make this decision. The traditional public school system today divorces parents from planning and curriculum. Private schools ask for and receive parent input through volunteer boards and committees.
Public schools teach curriculum which violates the religious and moral principles of some parents.
Private school offers parents more input into the course of study. Put aside political speeches, and get down to the bare bones. Don't force children whose parents have limited financial resources to attend public school. Politicians do this all the time claiming school choice would undermine the public school system. Competition in schools, just like in business, can lead to better education.