I absolutely agree with some clothing is used for health/sexual/wealth signaling and it works to some degree. But these simple ideas don't nearly explain fashion. If fashion didn't include a huge amount of delusion, it would converge. It wouldn't shift with each generation.
We are more than hardwired to find the most capable mate. We're also hardwired to pick up social cues so if a large enough group of people believe something, we believe it too. If everyone you knew started wearing those MC Hammer pants tomorrow, how long would you hold out? If people suddenly and entirely stopped wearing ties with suits, would continue to wear the most unnecessary accessory ever? Why does everyone in tech dress so similarly?