This reminds me of a quote about how MIT has a way of turning physicists into lawyers. What it means is that people who started school trying to be physicists, got overwhelmed with competition at MIT and end up reverting to law school after graduation because their confidence in physics was diminished. Where if they went to a regular school, their skills (and confidence) would have grown.
If you can't 'hack' physics (I correlate this with very high IQ, stoic commitment to research) it doesn't mean you'd hack medicine (Which needs decent IQ, amazing memory/recall and very good interpersonal and communication skills, and ability to handle stress, blood and dead bodies).
Today, there's no such thing as medicine-as-a-fallback. If you aren't solidly and deliberately premed for several years, building relationships with people who can write strong LORs, doing and documenting volunteering hours, and getting everything else in order, you don't stand a chance at admission to a competitive school.