The lottery for the good schools is a recent thing isn't it? Your friend got into a good school because she tested into it.
Also, having attended one of these schools (admittedly in a different decade), students who were not ready for the work didn't do well. Not to say those kids weren't also smart kids, but you had to be a certain kind of kid to mesh with the school.
It was a fantastic place, not just for the education, but for spending 4 years with a gigantic group of diverse, interesting kids, almost all of whom were truly brilliant. To this day I think it had more to do with my success than college or grad school.