also, IB schools don't always offer AP courses, right?

Are those schools, even if they are private, exclusive rated lower on the adversity because of a lack of AP courses?

Reading several articles and it looks like the top, when the students have great scores, have legacy and great extracurriculars and the bottom with adversity benefit from the system but the middle is the one that misses out. If you are in the bulky middle class and your kid goes to a really good school has great scores and lots of AP, will be in the losing group.