@Hanna - I realize that there are other goals that come into play in admissions beyond assessing academic strength. I even have words to such effect in the bit that you quoted from me.
But I still think that for Harvard, MIT, Stanford, etc, the LARGEST part of each admissions decision is an assessment (in varying ways) of academic strength. Yes, if you’re 6’5", 290lb, or your daddy’s name is on the library, that maybe becomes the overriding factor - but those are basically outlier cases relative to the bulk of admissions. And yes, even for mainline admissions, the decision factor on that last yes or no will not be purely based on GPA, rank, or SAT/ACT. But that’s only because those (and other) academic factors have already been applied to the screening process. The kid with the 26 ACT and 3.1 GPA, but a FABULOUS essay, who’s also a legacy (but not a development case), likely won’t get in, because she’s already been screened out at the first or second pass.