I don’t know how the negative feedback cycle started but it definitely exists — teachers are treated with contempt by both management and parents which creates a selection pressure that either favors or develops a certain kind of negative character trait in the job.

My school was very poorly funded. The shiny new facilities that everyone associated with the private sector were only ever provided as vanity projects by wealthy parents. The day to day funding for repairs, painting, food, resources, staff etc was rock bottom. Another reason to see how a bitter sentiment can accumulate over time.

So I guess the first of your two options? There is a constant influx of people who want to be good teachers. We squander it but passively knocking them down and it is very sad.