> However, I must mention that I been in contact with so many really bad HS staff (teachers, principals..) all with legitimate credentials, that I am starting to wonder about their significance? A principal should probably have some teaching experience, but seems to be like more of an MBA/business type of background?
Teacher raises and admin positions are all about box-ticking with the right pieces of paper. It's typical (though not universal) for admin to do the minimum time teaching (half-assing it, obviously) they need to for any kind of higher degree/cert they want (I want to say for a lot of programs it's 2 years or something like that) then move on, so yeah, many have little teaching experience—ask any teacher, nearly all teachers suck and don't know what they're doing the first couple years, that's just how it is, so you don't get good in that time, and you probably also don't get a sense of how periodic curriculum shakeups and such screw with teachers doing their jobs (not to mention their private lives, when they lose their evenings to some stupid new paperwork that you've introduced which could have been derived from other data you already have if you weren't a moron).
Education, Ed. Admin, and related higher degrees are ridiculous. You'd probably have to dig hard to find a program that's not a joke. The reason is that schools give zero shits about where your degree is from or what the program's like, just that you have one (and maybe your GPA, if it's for hiring—if it's just for a pay bump, they don't care about that, either, it's just automatic). There are lots of teachers/school admin. Consequently, many universities, even otherwise kinda-decent ones, have joke master's and PhD programs for teachers/admin, to rake in that sweet sweet teacher money, since the teachers/admin mostly just want 1) easy, 2) convenient (online or evenings/weekends, and as few hours as possible), and 3) cheap enough to justify the effort in a direct cost/benefit way (trivial to calculate from pay scales). The classes are nearly pure busy work.
If they don't just want to tick a box to get a raise or to go into admin and actually want to learn something, they get a non-education higher degree (usually in a content area of some kind—English, Mathematics, that kind of thing)
Source: am married to a teacher and, not through her, good friends with several others.