I agree with most of this. However, teachers' unions have done their best to prevent schools from paying teachers with less common skill sets (like STEM) more t

I agree with most of this. However, teachers' unions have done their best to prevent schools from paying teachers with less common skill sets (like STEM) more than teachers with more common skill sets (like PE). It's this aspect of lack of free market and supply and demand dynamics that prevented me from staying in the classroom.