"The idea that union teachers are "motivated to do the best job possible" is ludicrous."
My wife used to be one of those union teachers. And, while she was, in fact, highly motivated, most of the rest of the teachers she knew were an embarrassment. Her local "union leader" insisted that she and the rest of the "teachers" exit the school at the end of the day at the exact moment they were allowed by their contract. The union also told her and the rest of the teachers not to provide children extra help after school, because their contract didn't specifically provide money for that service.
After her first year she quit. Our two children have never set a foot inside a public school classroom, and they never will.
That illustrates the exact point that I brought up. :^)
Most public school teachers START dedicated and enthusiastic, but after just a short time the union environment sucks the motivation out of them.
The same thing happened to me as a union CNA that happened to your wife as a union teacher. I was told to not do any more work than was explicitly spelled out in my instructions and the overwhelming atmosphere at the facility was of a spiteful contest of wills between the union and management.