Here is a 1912 photograph of a crowd of baseball fans listening to pre-radio play-by-play reports of that year's World Series (Bosox 4, NYGiants 3) outside a building in Manhattan. Notice the formal attire of the group. Men actually used to wear suits with white shirts and ties -- and even hats -- on a daily basis. They all pretty much dressed alike.
Below is President Dwight D. Eisenhower throwing out the first ball of the season in 1959 for a Washington Senators game against the Yankees. Not much had changed in the 37 years since the earlier picture. Men -- and women -- still wore traditional clothes to sports events. The wardrobe choices of conformists and squares still prevailed.
Ten years later, the rules had changed utterly. Baseball fans, and just about everyone else except business executives, had abandoned suits and ties. Here is a photo from the stands as a casually clad crowd celebrates the New York Mets World Series win in 1969. Not a suit or tie to be seen.
In the 45 years since, two new trends converged. First, people became ever more involved with their teams. Second, sports teams exploited this enthusiasm to develop a rich new revenue source in team-themed sportswear.
Here is San Francisco Giants Pitcher Madison Bumgarner pitching a playoff game at home last season. Could you guess that that Giants' team color is orange?
And here is Bumgarner celebrating the Giants' World Series win in a sea of blue-clad St. Louis Royals fans.
A new conformity has been born.