Actually, teaching is quite a lucrative career in public schools: generous salaries, great health and other benefits, a great retirement package, 100% job security and summers off! 

People do get into teaching for exactly these reasons and it is why it is incredibly hard to get a public school teaching job. These old canards will never die!

There certainly are good teachers out there, but in my experience in public schools it is a remarkably small number. It isn't all the teachers fault either. Incompetent administrators and lack of any defined curriculum (outside grade level math) and most importantly school boards who know nothing about education!