I took all the science classes and was making 30+ on the MCAT practice tests, but ultimately decided I didn't want 300K in loans. Rather unfortunate to make life decisions on that basis, but after years of interest in residency I would owe like 500K and seeing how I hate paying my student loans every month I would not want 2-3k in loan payments until I retire if I can.
Also many doctors are trying to leave medicine since it has become much less about patients and more about money and paperwork, liability and insurance frustrations