However, the students aiming for PhD programs are scattered across all majors, instead of being concentrated in some majors (typically, about half of applicants to medical school are in biological science majors) and having to take a common set of pre-med courses (mostly shared with biological science major courses). So the “pressure cooker” competition for pre-PhD students in majors other than biological sciences is much less than pre-meds who look at every classmate and see a competitor aiming for the same limited number of A grades.
Pre-law students aiming for worthwhile (top 14) law schools also need high GPAs, but they are also relatively scattered (the largest concentration is in political science, but that seems to be only a fifth of LSAT takers).