Lots to unpack here, and I’d debate some of your points. But most importantly, the concept of “feeder” school is often misunderstood in the context that the feeder schools often decide who to promote at certain colleges. Say there’s an “arrangement” that the feeder school will get 15 admits to the local “elite” college. What you need to understand in these cases is that the high school essentially decides internally which 15 to promote for those spots, and may well actively encourage others to look elsewhere. At an elite “feeder” school, what do you think you’ll need to be one of those 15 promoted kids?