This one is not what it seems to be. Yes, it's occupational clothing, but it's not inspired by Butterick's marketing research that indicated that women interns of the 1970s (still a fairly small cohort at this time) wanted or needed to sew their own shirts - either strictly professional or in the weird ruffly version.
Although this isn't stated anywhere on the pattern, I believe that this is a tie-in to a medical drama television series called The Interns, which ran in 1970 and 1971. The series itself was a spin-off of an apparently mediocre movie of 1962, also called The Interns.
Dr. A. would appear to be modeled on Sandra Smith, who played Dr. Lydia Thorpe. Here's the only (regrettably muddy) image I was able to find of Smith in this role.
I assume that the program attracted a fairly young audience, so this pattern would probably have been targeted toward young women (notice the fairly limited range of sizes.) This gives the whole enterprise an odd cultural tension, as it seems to play to both home sewing, a very traditional female activity, and the career of physician that was beginning to become more widely available to women. Perhaps dressing up like a doctor was the first step toward thinking that one could actually be a doctor.
