Social-signaling games explain lots of weird fashion shit. See also: recent-model-year obviously-expensive trucks; expensive rims and other mostly-cosmetic car mods; "legible" clothing generally. Lots of it's about externalizing "identity" to ensure the observer can easily tell "who you are"—lots more is simply about conspicuous consumption, literally showing you have money to burn (except that if you just burned it, that wouldn't leave you anything to show people that you'd burnt it—you have money to burn, but not enough to burn without making sure people know you did so, which is the domain of the actually-rich, for whom having tons of money is assumed such that overt attempts to demonstrate it just look desperate and raise questions)

It even happens within counter-culture groups or those who claim that fashion doesn't matter, over time—they develop clothing-related signals and in-group markers. Consider the tech bro in the $140 hoodie and $120 rock-climbing-oriented "tech pants" and $300 hipster throwback work-boots telling you very seriously that they immediately dismiss anyone who comes to an interview in a suit, as a poseur.