I would like to point out that, while Harry Bernstein may be correct generally about teacher salaries, he is dead wrong about those in California.
Legally, in California, a beginning teacher cannot receive less than $20,000 a year. This would be much higher if it were not for the unions.
As a management negotiator for schools since the inception of the collective bargaining law, I have tried repeatedly to get unions to bring beginning teachers' salaries closer to $30,000 in many districts. But unions don't want high salaries for beginners. That is not where their membership is. Unions refuse to negotiate other than on a percentage basis, and this gives top salaries more. The aim is to get the top salary as high as possible.
For many teachers, teaching is a secondary income. In one district in which I negotiated, I made an analysis of the family income of all the teachers. It averaged about $59,000--putting these families in the top 5% of all family incomes in the United States. Only about 4% of these teachers had single incomes in the family.