I'm sure you and your wife and your colleagues are great teachers. I'm also going to assume you teach at a suburban school. I think you'd find that the work ethic in the big city school system (DC in particular)is much, much different.
John Stossel, from ABC is about the only journalist I've seen tackle this problem. He sent a hidden camera into a NYC school a few years back - it was terrifying and a cold indictment of many of the teachers in that particular school.
Many, many teachers are dedicated professionals that commit their lives, daytime and night, to the education and development of their students. Sadly, in the inner-cities (where the students need the most support), there is a much greater percentage of teachers who are there just pick-up a check.
I don't teach, however, my wife's school is actually urban, the toughest school in town with the highest poverty rate. Our town is mid size that may make a difference, also Texas has higher standards than other States when it comes to certification. I do know teachers in Dallas though with similar stories, of course, there are some that do cut every corner, but I think they are the bad apple in the lot, not representational of the whole. I would hate to visit DC or Chicago schools..
I will give you though that one of the biggest obstacles to teachers is other teachers. They often act worse than the students when it comes to gossip, complaining, and playing relationship games with each other. My wife avoids the teacher's lounge so she doesn't have to listen to it. Of course, she goes in with the attitude that this is her mission, and that makes all the difference.