They literally don't make shirts like they used to. Notice that this gentleman is able to raise his arm without his shirt escaping from his waistband and exposing his stomach. This is because his shirt has high-cut armholes. These are more difficult to put on but infinitely more practical to wear. Fred Astaire always had his armholes cut extra high so that his entire suit did not move with him when he danced. In the 1970's, manufacturers began making low-cut armholes because it makes the assembly line a fraction more efficient, at the price of making wearing the shirts an exercise in frustration. Shirts with properly placed armholes for either sex are virtually impossible to find nowadays.
Also note that the seam between shoulder and sleeve on men's and women's clothes alike was properly placed, without the "dropped shoulders" style of today, intended to conceal good posture.
And observe that these ladies' suits, like all women's clothes before the 60's, have darts beneath the bosom to conform to the shape of the female body. Just mull that concept over for a moment: women's clothes designed to fit women's bodies.