John Derbyshire puts a lid on it
The other day I stepped into an elevator while wearing a hat. Seeing ladies in the elevator, I removed my hat. One of the ladies, who was of a certain age, complimented me on my manners. “Not many men would know to do that nowadays.”
Not many men need to. As someone or other has noted, ours is the first civilization since antiquity in which the generality of people do not dance and do not wear hats. This common hatlessness seems to have started around 1960, like so many other malign developments. I have heard it blamed on John F. Kennedy, our first hatless president, though it seems to me more likely that the automobile industry is the true culprit. The aerodynamic, low-ceilinged style of the post-WWII auto body is just not compatible with hat-wearing. In any case, whatever role JFK may have played in the change was canceled out by his wife’s having popularized the pillbox hat, keeping elegant women hatted (and “milliner” a word in current use) for another half-decade.