As a history buff, I am always interested in how smoothly things change over time, yet how much remains the same. The whole world doesn't wake up one morning and say, "No more hats!" You see less hats on men these days because of the widespread use of cars, and the overall tendency for men to work indoors. The guys who work outdoors, as most men did up until about 70 years ago, still wear hats. The style of hat has changed, but not the hat.
Beginning in the 1940s, working outdoors started to have a negative stigma. Men wanted to be seen as thoroughly modern. A hat told people that you had spend a lot of time outdoors, possibly walking because you didn't have a car. But a hat is still a very important thing when you have to spend time outdoors. It keeps your head warm and provides shade for your eyes. The solution was for men to start wearing baseball caps.
|The author in a golf hat|
Hats are meant to be worn on your head, and some men feel naked without them. Don't ask him to take off his hat, unless you mean it.