Here are some numbers:
140,000 people apply to medical school every year.
We will say our "sphere of competitiveness" is encompassed by 3.60+ GPA and 30+ MCAT. This pool of applicants consists of 40,600 people (we've already eliminated over 70% of the applicant pool). If we want, we can include people with 3.40+ and 36+ MCATs to be in this competitive pool as well, so we'll add an additional 1400 applicants. This increases our pool to 42,000 applicants, a mere 30% of the original applicant pool. 32,200 are accepted, which is ~77%, meaning more than 3 in every 4 applicants in these categories are accepted! At this stage, it's more like who isn't going to be accepted than who is and we've so far only considered stats! More people will be screened out by lack of clinical exposure, red flags, late applications, applying to only Harvard, Hopkins, and Stanford, bad letters of recommendation, exceptionally poor writing skills, and so much more. Then, once people get to the interview stage, a poor interviewer will be screened out. These are a lot of things that work to screen out a mere 10,000 people from our "sphere of competitiveness", which can be done very easily.
Now, does this give you insight as to how the minds of adcoms work? No, probably not, and since every adcom and adcom member is different, you're going to be hard-pressed to find a way to get into the heads of every single one.
My point here is to show you that 1) this process is not random and 2) in the aggregate, it's more about "screening out" than "letting in" for the vast majority of applicants; the letting in part happens for the last few to survive these screens.
Hopefully this provides a different perspective on your musings.
Edit: Numbers from AAMC Table 24 (
https://www.aamc.org/download/321508/data/factstable24.pdf)
