OK, I've done something that annoys me on MN and haven't RTFT. Beyond reply 10. Because I can guess what it all says.
Here's my take regarding schools:
It is my belief that the demographic of a school's catchment is what is important.
You read, and maybe know of- a school in a difficult catchment that suddenly improves dramatically, the OFSTED goes from 'Needs Improvement' to 'Outstanding'. Hooray! But-
Why? Because of the arrival of an inspirational, influential (possibly specially funded, cf London '90s) Head. Vision. Discipline (along with expulsions). Uniform (😉) and the peeling away of the disengaged.
But the day they leave, the school crumbles.
Contrast the naice, middle class school in the naicevleafy catchment. An easy catchment. Many schools in these areas will be considered 'good', if not outstanding.
They can trundle along for years being 'good'. If their Head leaves, they're replaced with the same.