Only a shred of evidence, but a shred nonetheless:
Kurt Gray, a co-author at the University of North Carolina at Chapel Hill, and his colleagues investigated thousands of shoe purchases made by women who move to different cities, showing that women adopt the local trends when moving to wealthier cities but ignore them when moving to lower socioeconomic (SES) cities.
“In other words, women want to look like the rich girls, and different from the poor girls,” said Gray, an assistant professor of psychology in UNC College of Arts and Sciences.
…Because fashion choices are hard to quantify, they used a straightforward number: the size of high heels [for luxury purchases].
Source here, paper here. Perhaps this eventually becomes a theory of fashion cycles, if the rich women feel, after a while, that too many other women are copying them. By the way, the researchers seem to believe that comparable mechanisms apply to men too, albeit not for high heels necessarily.
For the pointer I thank Charles Klingman and also Samir Varma.