For example [vaguely]: writer creates a character who behaves like X, despite nobody actually behaving like X in real life. Then characters behaving like X become a wide-ranging trope. People in the real world begin to think it’s normal to behave like X, and subsequently start actually behaving like X themselves.
Any actual examples of this phenomenon happening?
You focused on the trees and lost the forest.
OP’s question was about people actin a particular way that originally seemed ‘unrealistic.’
Whatever the actual music was, it was McLaren et al that got people wearing purple mohawks and using safety pins for jewelry.