Most (>80%) frosh pre-meds do not complete the pre-med courses for whatever reason (perhaps a few C or B grades will do that, or realizing through pre-med extracurriculars that clinical work or serving the disadvantaged is not for them). Many of those who do complete them do not apply to medical school for various reasons (e.g. realizing that their grades or MCAT are too low, or no longer interested). Of those who apply, most do not get any medical school admission.
So anyone going to college intending pre-med needs to consider other academic and career paths in the likelihood of not going to medical school.