Assuming that the teachers to which you're referring are those employed by government [i.e., "public"] schools, I would add to that list:
1) The fact that many of the teachers employed by government schools don't have much training in the particular subjects to which they've been assigned to teach because of time being spent having to endure sitting through the required types of classes mentioned in the OP.
2) Having new teachers being "encouraged" to join teachers' unions that, on the national level, are controlled by radical left-wing persons who will always promote leftist politicians such as Hillary (It Takes a Village) Clinton.
3) Having to work under such conditions as noted in the OP which allows those teachers who honestly want their students to learn the goals and objectives for their class(-es), but cannot because they aren't, by school policies, permitted to enforce much class discipline towards those students who are wont to disrupt their classes. This is partly due to the "required attendance" policies that only state that each student is required to occupy a seat in a classroom but isn't required to learn anything of the subject matter being taught.
4) Having to work alongside teachers who will either "teach to the 'test,'" i.e., teach the answers to the standardized tests--something which is supposedly illegal but still occurs in many government-run schools (e.g., GA).
5) Having to work alongside some teachers who, upon achieving the status of "tenured," often times either allow the students to "run the class," or actually don't even show up for class--leaving the actual teaching to be done by less-than-well-qualified persons who, in many cases, don't even have a teaching degree--much less being certified.
Having taught in high school level classes for 15+ years, I'm well aware of what goes on in many classrooms of government-run schools.
This isn't to say that every teacher in every government-run school is like the above-mentioned ones. There are many very dedicated, hard working teachers in many of our government-run schools who are both under paid and under appreciated by both their respective school administrations as well as the parents of the students they are tasked to teach. We have some of these amazing teachers right here on BB.
Given as many negative factors that exist in today's government-run educational systems, I'm not surprised that there is as much turnover in the teaching profession as there is.
Some 50 or so years ago, teaching was generally considered as an admirable profession, but once the national-level of the teaching level was taken over by the bunch of ultra-leftist bureaucrats as it has been, the general public's estimation of teaching as an admirable profession has declined.
