When people very seldom flew, they always wore their best clothes. Look at real old photos from the 20, 30's and 40's of baseball games. All the crowds wore their best clothes and hats were in style.......
Most people were still dressing up to fly, through the 1980s!
OTOH...people began to NOT dress up to see a Broadway show nor to attend an opera, in the early 1970s. They were stared at, in disgust, but sadly, that way of dress soon became common as the 20th century ended. Today, anyone who can afford to shell out $100 and sometimes very much more, to see a lousy play, has more than enough money to at least buy and wear something better than scruffy, stupid looking, what was once considered to be low level work clothes; but most don't!