Lets use me as an example!
I was all set to go to PCOM. Awesome, I thought to myself. Philly is cool. Then Touro, very close to my hometown and in a city i prefer to live in, tells me I am accepted. It is a very new school at the time, but I go "whatever. I want it" and I book it to Touro. Now I could have been at a few different DO schools. I applied super late and still got into a bunch of places. But I *chose* to go to this nearly brand new school because it fit with non-academic things I was looking for.
So PCOM loses a student that, I think this is safe to say, they viewed as average or better student to a school where I would be... let say "not in the bottom section".
So two things go on here at once. 1) my story is not unique. It is the story for 2/3 of my class. That they had acceptances to, superficially, much better schools and chose to go to Touro because they wanted to be at this school specifically for x y or z reason.
2) those 90-ish people in my school mean that there are 90 "accepted" spots that were declined at better schools. Those schools will fill their spots by either accepting someone accepted elsewhere, that puts a hole in THAT schools roster... or (as happens eventually at some school) the school takes a flier on someone who would normally be below the acceptance threshold but they take a flier on them to fill an empty spot in their class roster.
1 or 2 people across all of DO education is considered "lucky people." 160+ people all having this done is called "lowering the minimum acceptance threshold". At no point does adding more schools make "well qualified" students sprout from the ground. It just redistributes where the students can go. New schools fill with a mixture of low-quality and high quality people. The low quality are probably just passing the threshold, the high quality are sniped from other schools rosters, and the other schools have to react in ways that will eventually lead to *someone* taking a lower quality student.