>Right so you’re saying they could randomly pick from their applicant pool because right now only perfect scores apply.

This would actually be a reasonable way to go. Set a cut off ACT/SAT/GPA and just do a lottery for kids that are above it. Actual fairness. Of course thats not what HPY + Stanford etc. are interested in. They are still just finishing schools for the elite. If you want actual meritocracy go to MIT or Caltech

This is an excellent question--that should be answered by data. Is there a thresholding effect? It could be that say there's not much difference in a hundred points in the SAT. But, maybe GPAs actually are more predictive. I assume that rec letters are useless to first approximation unless the recommender writes something about the student that raises flags.