I don’t know why they haven’t switched over to static displays at the big shows.
Maybe because that's a ridiculous idea? It's not like hi-fi actually suffers the same restrictions as an auto show.
I can't imagine traveling to an audio show (and many people travel a long distance) only to look at some silent display. The first thing I'd want to know is "why can't I hear these?"
Audio shows are were many people encounter equipment that they'd never be able to hear anywhere else. That includes the fun of hearing beyond-one's-mean exotica, or finally being able to check out a brand one may actually be interested in (many people don't have any high end stores anywhere near where they live). Or one may have a surprise encounter with a brand they hadn't known of, or considered before.
It was due to hearing the Thiel CS6 at a show that led me to end up having those speakers in my home.
It was due to hearing MBL speakers at shows that ultimately led me to owning MBL speakers.
It was due to hearing the Hales Transcendence T8 speakers blowing away everything at a show that led me to purchasing the more affordable T5s.
It was due to a shockingly good sound from Joseph Audio Pearl speakers at a show that led me to investigate that brand, ultimately leading to my now owning JA Perspective speakers.
