So law has a lot of blind recruitment but at the end of the day moving through the ranks demands a certain level of post uni funding so it's a bit private school self selecting.
Media - say you want a job in tv, the normal start is kit room or runner.
To move up to Production you need to be able to talk to people, lots of people, understand them and break down the barriers that prevent them telling their story on screen.
Your private school kid with no experience of a mate with school meals or just being aware of where the local food bank is, is pointless for Bake Off. They are never going to understand how practising a showstopper will cost some serious coin. You need people who can cover a mates embarrassment, fix it and move on. A normal state school skill set.
And that applies across all daytime, documentaries, fly on the wall.
Obviously, people drop out, can't afford to fund the gaps between jobs, so by 30, the ratios shift and the ones that have clung on are often private school. But I just ask - where do you live, travel, tell me about the people you've met... And that's how you find the niche experts and the interesting bus drivers, school dinner ladies, etc.
Academically - honestly if your parents have paid so much for education, they always add the school in. DH sometimes does the medic interviews, he can tell, they all nod to each other when they come in on mass.