“I just know that, despite being my personal best, they weren’t THE best”
Hmm. You don’t seem to be hearing what many people are saying. Elite privates mostly aren’t filling up with “THE best”.
The majority have some hook or another (including about 5% who are in solely or mostly because their parents donated a ton of money to the school). Roughly 10% of Harvard’s entering class is for those who are the very best academically. The rest are indeed awesome in usually many ways.
But, and this is something I’ve pointed out before: There is this wide discrepancy between how difficult it is to get in and how much opportunity is on offer between colleges in the US.
The example I gave is that a CS major at UCSD (or heck, even SJSU or CalPoly SLO) will have about the same opportunities open to them as a Stanford CS major or Cal EECS major. Yet it is waaay harder to get in to Stanford/Cal EECS than UCSD/SJSU/CalPoly SLO CS.