Even though she advocated plus sized clothing I was able to find size 2 pants called "Just Right."
Yes, she realized that women came in all sizes and shapes, not just tall slender athletic cut. Liz Robbins (wife of Royal Robbins) was another advocate of differing clothing cuts.
For the guys - the hip to waist differential is different for different cuts. Curvy cut usually has a hip to waist differential of 10” where modern cut has a hip to waist differential of 5”. Athletic (and other) women come in both shapes. Another aspect is the short/regular/long concept of pants.