The analogy you're trying to use doesn't make any sense. MDs are not cabs as DOs are to Uber. Physicians are definitely not cabs as midlevels are to ubers... often a midlevel is a scooter with a broken GPS that either arrives unsafely or calls an Uber when it can't figure out where the patient is going. The midlevel in this analogy also produces at a faster rate given their foregoing of medical school and residency.
The idea that numbers rule the discussion is misinformed. If DOs far outnumbered MDs it wouldn't mean anything unless they were also involved in the residency interview and ranking process, and very few DOs hold positions at prestigious programs. Even when they are, there is no guarantee. For example, the PD of the Emory anesthesiology residency is a DO, yet that program may never accept a DO resident. I hope to one day hold an academic position and help aspiring applicants meet their goals, but I'd be lying to myself if I said I wouldn't think twice about taking just any DO, knowing what I know about some of my classmates and their progression. That may be how I'm thought of at these interviews: I know for sure that many residencies are suspicious of any student trained outside of their own med school program as there is no guarantee of their training. Medicine should not be a democracy where all voices are held equal, nor should it be a free market, because you will find very quickly that the products will diminish in quality.
I guess my point in bringing midlevels into this bypasses your point about raw numbers. I said it because the ACGME, COCA, LCME...every group pretending to associate itself with the betterment of physicians has a responsibility to follow standards and train effective physicians, no matter where those physicians come from, and the alternative poses a threat to the safety of our medical system. It is much more important to me that they realize that the overall unification of physicians is more valuable than establishing a mote of prestige in a small program at a small part of the country for a short period of time, and recognize that regardless of initials or location of medical schooling there is a common appreciation of standards of training. The future of physicians and residencies trends toward a failure of specialties to resolve their conflicts...a failure to unify against bigger threats to the profession like hospital administrators and the popular narrative of neutering medical licensure to save money at the cost of safety. Our midlevel "counterparts" are inclined to believe the process is democratic and a free market system.