While there are certain special opportunities that may be given to only a small number of excellent performing students, that does not mean that the other students will not also have special opportunities. Most opportunities during college are not closely tied to class rank. There are also plenty of special opportunities at less prestigious schools, in addition to prestigious ones.
For example, I had the opportunity to be one of the first employees at what is now a well known tech company whose name all on this forum would instantly recognize and whose founders are billionaires. I did not take this opportunity because at the time they were a small and little known startup. I got the impression that they were desperate to get people to join them. They were certainly not limiting hiring to just students with a high rank in class. The opportunity occurred because the company was formed by a group of students in the college and limited initial recruiting to the college they attended. Had I attended college elsewhere, I wouldn’t have this opportunity, but I might have a similar type of opportunity at a different well known start up.
Early in college, I was interested in both engineering and medicine. For the latter, I was especially interested in biopsychology and behavioral neuroscience. I had the opportunity to do research in this field. This opportunity occurred because I contacted someone at the med school doing research in the field who was looking for assistance. They did not ask about my rank in class. I started out doing basic things like patient interviews and moved on to more complex things as I my performance was observed.
I had a part-time off-campus tech job while a student, which I think was a key experience for my first full time job after graduating. I learned about this job based on a flier I saw on campus. I contacted the company, dropped off my resume, did a short interview, and they hired me. I did not get the impression that the opportunity was limited to persons with high class rank. They seemed to focus on other criteria and be impressed by other things we discussed in interviews. At the time, I did not have a car, which limited part time job to companies within a short bike ride from campus. Having tech companies located so close to campus that are used to hiring part time students from the college and have fliers on campus led to a special opportunity.
I could list many other examples, as I expect could most college students on this forum. The point is there are many types of opportunities that do not closely depend on class rank or the college being prestigious. These opportunities may require initiative from the student, rather than expecting someone to hand the opportunity on a platter to the top of the class.
How does a student know if they will be in bottom quartile or not? If you mean bottom quartiles test scores, that’s a 790 math at MIT. I wouldn’t assume a student scoring a 790 instead of 800 is going to have a bad experience at MIT. Similarly I would not assume 730 EBRW means bad experience at MIT.