It starts with non-religious elite private schools. If your family can afford college level tuition for a K-12 education, there's a tacit agreement that one of the elite universities will have a spot for you. (Seriously, one school near us charges almost $40K for grade school tuition, but it's in the top 15 or so among elite boarding schools.) If you can get into and graduate from a Harvard, Yale, Princeton or similar, the school and its alumni network will not let you fail.
I've noticed something along this line as well having gotten to know one of my son's friends and his family over the last year or so. From outwards appearances he fits the stereotype of the black kid who is destine to fail. His mom, baby sister, himself, and a couple of cousins live at grandma's house, little sister has a different father than him, and neither dad is around. In actuality he is a really smart kid but hasn't been afforded many opportunities to learn anything other than what is taught at public school. Even comparing him to my kids there was a huge difference as mine have things like music lessons and have a bunch of people who can teach them all sorts of things and take them all sorts of places even if we are not the private tutors and elite school type my kids had a lot more opportunities than he did.
I first met him when his grandmother came over because I was taking a class with her and she wanted me to help her with her class project and he came along. To keep him busy for a while I handed him a planetary gear system similar to that in a car's automatic transmission I built out of legos to show my kids how one works and told my oldest to help him figure out how it works if he gets stuck figuring that it would keep him occupied for a while. That only lasted about 10 minutes before he had a good idea of what was going on and wanted something else so I went and found a lego mechanical clock I had made as well to show my kids how things work for him to figure out. It isn't that mom or grandma didn't want him to not learn things it was just they lacked the knowledge of even how to expose him to things.
Fast forward about a year now and he has gotten involved in cub scouts which exposes him to a bunch of new stuff, likes to come over to be with my oldest and do things he otherwise wouldn't that really are sneaky ways to educate them, and has someone who he can ask about math and science. He is doing better in school and has been placed in the advanced group or regular group instead of the low or regular one and has found that he has an interest in mechanical things. Even last nigh when he was over finishing his pinewood derby car he got to learn something when we went to test it, find piece of masonite to lean up against a wall in the basement for it to roll down and then across the floor, and I pushed some wheels into block of wood that I quickly hollowed out and raced them as we made changes to the block of wood. Now I could show him how putting different amount of weight in the car affected how fast it would reach the other side of the basement. Showed him that putting the weight in a different spot affects it and how aerodynamics also affects it. Stealth learning at its best and seems to work well with boys.