Well, Wisconsin got rid of unions and they're hemorrhaging teachers.
Meanwhile, there's been discussion of loosening teacher licensing requirements particularly in non-core areas. I know some teachers in favor, but most teachers I know feel that the mistake there is thinking that a teacher teaches a subject. That's simply not true. A teacher teaches a student. Not every person who is skilled in an area belongs in front of a classroom. Indeed, sometimes the people who are best at a subject struggle while teaching it because they never had to work to understand it. They have a hard time relating to the students who don't get it the first time.
I digress. My point is this: it seems as if the go-to solution in education in many places is to lower teacher's compensation, lower the requirements for being a teacher, and then complain about the lack of quality teachers. If you want a better service, you have to offer better compensation. I feel this is simple economics.