What got you into an Ivy League?

Answered

This is not my own stats obviously, but from students I've worked with, you generally need something like a 3.7+ unweighted GPA and a 1500+ SAT/32+ ACT to be above their academic thresholds. That also depends on demographic factors; some students, especially ones with "hooks" (legacy, recruited athlete, underrepresented minority background, etc.) can get in with lower stats. Without a hook though, there's not much of a shot below those numbers. But you definitely do not need a 4.3 or a 1590/35 to be considered for admission (and nor would near-perfect academics guarantee you a shot at acceptance).

As for extracurriculars, you are definitely seeing the outliers. The Ivies obviously reject a ton of students but that's because they get tens of thousands of applicants every year. But the more "normal" students who get in just don't get articles written about them or have people gossiping about them. It's absolutely possible to get into these schools with a few really strong but reasonable ECs—like leading an interest club, being the editor-in-chief of a school newspaper, being a captain on a varsity sports team (or academic competition team), etc.

The thing that really characterizes the types of students that get into Ivies and similar schools is a well-developed interest or passion in a specific area, especially an interdisciplinary area. Students who have a real talent for something and have shown that through work, whether that's writing, sports, scientific research, medicine, visual arts, etc.—those are the ones that have a good shot of getting into Penn or Yale or MIT or wherever else. You'll see a lot of people with "empty" stats get rejected from these schools because they weren't able to demonstrate that they actually cared about something and had put work into that thing; for these schools, having a bunch of accomplishments but no discernible focus can come off as careerist, and they tend to shy away from that. You don't have to do the absolute maximum like the cases you're mentioning, but you do need to show that your interest in whatever academic area you're pursuing is more than just "this is what I need to do to make a lot of money someday."