Isn't everything a ploy foisted on us by fashion designers? Just think how easy they were to push at the time. Cleanliness (polyester, just throw it in the wash) and they were 'leisure' suits, comfortable for the wearer and convenient for everyone with little fashion savvy.
The flowered or paisley shirt were 'plumage', maybe with a gold chain or two... sign of a good 'provider' for females.
Meh. I think science has established that sometimes traits for selection don't have a basis in utility. (or are at least a few degrees removed) Birds are especially ripe with examples, look at things like Peacocks, Bower Birds, Birds of Paradise, etc.
