Good posts.
For an issue which many consider either fruitless or settled, its ability to endure is amazing.
Listened to this podcast from just a couple days ago:
https://parttimeaudiophile.com/2021/09/09/what-are-meta-materials-do-expensive-cables-matter-the-occ...They discuss the profit margin of cables, the different ways to listen to hear differences, the physics involved, the continued financial success for the industry despite the unending "snake oil" claims, and more. Possibly of interest.
I'm gratified to see the example of umami mentioned. It's appropriate, I think. Many people hear differences; many companies are experimenting with designs and materials resulting in further differences heard.
To my mind, there's a very good chance that scientific explanations are lagging behind; that's the history of science, right? The unexplained rises up in our experience and then we try to devise tools and measurements to measure, predict, and control experience.
But even if that's not the case — let's say that we cannot find a tool & measurement approach to explain why differences are heard. Let's say we discover that, like currency, this is all a huge social construction — people inventing a symbol system with no basis in physical reality. Last I checked, language and money, sports and religions, are all considered real enough by most people. Anyone who considers socially constructed realities as fake is hereby invited to send me their money. (Friends and Family on Paypal is fine.)