I think fashion generally is more about human boredom with aesthetics, than with a cultural delusion, or daydream. People have, for quite some time, craved for fashion, design, architectural, etc, change for the sake of change. Obviously we could live quite well and without a problem if we all dressed in blue overalls, or just practically (not fancily) for an environment. Fashions are just, well, nice, but not a true necessity.
I think delusion comes into it when you see someone dressed like an outlaw biker for example. The delusion is – I’m tough, nothing can beat me, I will fight to the death, I’m immortal. When of course, in reality, they are as frail as you and me.
Or, an overweight middle aged woman, dressed like she is a 17 year old love goddess, in skin tight jeans and top, for example.