🙋👍
There was once a time, when yes, these boarding schools were absolutely "FEEDER SCHOOLS" and unless you got really horrible grades in some subject/s ( and your parent/s grandparents, etc. hadn't gone to the college/university ), the student applying was in "trouble" [perhaps weight listed at best], and then there were the ones that did NOT take you if you were Jewish...like Williams, in the late 1950s ) you were accepted.
But that began to change once the newest and dumbest subsection of WE HAVE TO HAVE *non-white, EXCEPT FOR ASIANS, students from public schools, whose classes and grades don't really meet our requirements, admissions.