Part of the reason behind restrained increases to med school spots is because traditionally they tried to get very close to full placement to residencies. In recent years, med school attendance has grown much faster than residencies, and that would be a very terrible position to be in to go $400k+ in debt and pass med school to only get stuck when you don't place into a residency the first round. https://www.aamc.org/news-insights/us-medical-school-enrollm...

EDIT: There are also separate osteopathic graduate schools and foreign med schools (Caribbean) that aren't limited by the AMA and still funnel thru the same match program.