In Becoming a Student Doctor, students focus on the pressure of applying to college. A couple of documentaries frame this unit. So I won't directly answer the questions. 🙂
Acknowledging the original question of "top undergrad" vs. "top medical schools," there's much more pressure on admissions officers involved in college admissions. So far, there is no "varsity blues" scandal for medical school admissions.
Undergrad admissions includes admission of transfer students or international students, so the "game" is much broader. Maybe as an aspiring Ivy-plus leaguer, there's the problem of competing against children of legacies, donors, and significant world leaders that is invisible to you (and how they are prepped for the process). At most medical schools, we don't consider transfers or international/undocumented applicants (unless stated) for entering class seats.
Medical school admissions are not appealing to just one demographic group of high school seniors,. nor can we leverage their metadata to micromarket you to apply to their school (and you'll send 100 applications to get into a school because... you want to shoot your shot). Non-traditional enrollees make up about half of each entering class (generalizing for all schools, including the "brand names"). We like maturity because in medical school, you ultimately take care of patients, as early as first week of classes. That's a higher expectation of responsibility that is not present in undergraduate admissions.
You can also drop out of undergrad or transfer out if you feel you need to; it won't affect your future as much as you think it would. It is much more difficult to return to medical school or start elsewhere (it can be done, but it's not easy like undergrad). You also are under much more scrutiny for "professionalism" as a medical student vs an undergrad. We look for professionalism in medical school admissions in your application and our interviews; undergrad admissions doesn't scrutinize as much. You generally can't "go home" to the medical school that admitted you once you leave like you could return to your undergrad program (including non-degree postbac student).
Plus you always have backups in undergrad admissions: some options include a "guaranteed spot" if you graduated top in your high school (Texas), or you can go to community college. There's a national discussion on whether a college degree is worth the cost, given so many millionaire "tech bros" probably dropped out. The discussion for professional school is focused more on debt, but there's a societal need for healthcare workers across the board; no one in society is questioning the value of an MD, DO, DDS, etc. degree except under the context of paying back loans.