A few months ago, I read, on Quora, a piece about a historical costume fact of which I was ignorant, and which was genuinely interesting. The piece can be read here (scroll down to the answer by Randy Long, former retired systems engineer; that's the piece I mean).
The gist of the article is that, in the 30s, 40s, and 50s, when men in America and Europe typically wore suits as a everyday matter, suit jackets were cut differently. Specifically, they were cut with higher armholes that conformed to the torso much better, and as a result those jackets did not ride up when the wearer raised his arms, in the way that men's suit jackets (and women's suit jackets, for that matter) do today. So the earlier suit jackets looked nicer and, in addition, were more comfortable to wear.
Why the change? Because it was a lot cheaper to make ready-to-wear jackets with the low armholes--particularly for the ready-made clothing market.
If I ever make enough money again, I will order one custom-made suit, I think, with proper armholes.