To be sure, athletes and legacies aren't admitted unless they are on a par with other applicants in the pool. But when you only have so many acceptances to give out, something has to give. Then there is the advantage that comes from having a different background than most great applicants whom a university sees. A prestigious university wants to create a richly diverse mosaic of students who will serve to teach each other through the life experiences they have had. They can reflect the ethnic, racial, or economic background of the student.
Prestigious universities pride themselves on the learning that goes on outside the classroom.
By assembling a class where every student has a story to tell, the university hopes to provide the richest possible education. It is highly unlikely that every university you apply to will already have on campus or in its applicant pool one or more individuals exactly like you. Sure, the acceptance may not come from the university you've been dreaming about since were in the seventh grade. But no doubt it will be a very fine university, one that will continue to challenge you in and out of the classroom.