"Teachers are the ultimate tools"

You can say that again, I worked at an FE (hah!) college for a while, and there wasn't one of them that didn't deserve stabbing.

it's because many of the good ones left in disgust (or refuse to join) a system of idiot bureaucrats who are more and more is taking decisions about education away from those most qualified to make them, and instead treating the teachers simply as replaceable resources to be blamed for everything but not given the authority to change anything?

Just perhaps?

Na. Some of them need more bureaucrats, not less. The amount of schools my business deals with where the Teachers think that they order stuff and then it is paid for by magic and pixie dust without them having to ask if they can buy stuff or telling anyone they have... ARRGGGG...