You're conflating actual value with perceived value. It's well established that perceptions matter and people make decisions based on this all the time.
> The whole Julia Roberts trope resonates exactly because it happens in real life.
No, it resonates because it's a feel good story. I'm sure it happens, but most of the time signaling is perfectly accurate. If you don't believe me, exchange clothes with a homeless person and try to go shopping on Rodeo Drive.