The music video for "Come As You Are" by Peter Wolf portrays exuberant everyday life in a small town during the late 1950s, and by the end the whole town gathers together in a crowd as though they'd all caught dance fever from the future.
One of the key examples of "iconic Fifties life" that they bring out is the 10 year-old kid who's all dressed up in his Davy Crockett gear. Not because he just came from a school play about frontier life, but because that's just what boys were into at the time. In fact, the Crockett craze was part of a broader mania for all things Western during the late '50s, among both children and adults.
How similar was that phenomenon to the trend of cosplay in the Millennial era? It was a full costume of the icon — clothing, hat, and prop gun — rather than a t-shirt / backpack / lunchbox with the icon's image on it. The icon was a specific character, Davy Crockett, rather than a generic type like "frontiersman." The children were role-playing as the character, rather than dressing up that way while behaving normally. And it was a mass phenomenon mediated by the mass media, rather than a strictly grassroots sub-culture or counter-culture.
Daily life in the Mid-century was relatively unexciting, especially for children during the heyday of Dr. Spock, smothering mothers, Levittown subdivisions, and drive-ins where the customers physically cut themselves off from each other. Role-playing as a figure from the Wild West gave them an escape from the cocooning culture's insistence on parking yourself in front of the TV set rather than wandering around the neighborhood, clipping your fingernails and brushing your teeth in the proper way, and remembering to drink your Ovaltine.
At the same time, competitiveness was low and falling circa 1960, so kids back then did not make costume competitions and one-ups-manship a part of the Crockett craze. And unlike now, there was no pseudo-slut counterpart among girls — attention-whoring being another aspect of the competitiveness of today's culture. It was also restricted to kids who were about to go through puberty, rather than adolescents and young adults.
It seems then that cocooning is what brings this trend into being, and that high or low levels of competitiveness only shape its expression.
I don't remember anything like the Crockett craze during the nadir of cocooning in the '80s. There are pictures floating around of D&D-themed cosplay in the late '70s and '80s, but that must've been damn rare. There are only a handful of gatherings pictured, as opposed to the endless examples you can find of kids in Davy Crockett get-up or of contempo cosplayers.
At the height of Hulkamania, we might have worn a t-shirt like Hulk Hogan's, or played with ninja weapons during the Ninja Turtles craze, but we never got fully dressed up in character for role-playing, let alone dress that way in an ordinary setting like hanging around the house. Everyday life had enough excitement back in more outgoing and rising-crime times that it wasn't necessary to pretend that you were part of a Wild West culture.