Perhaps. I cannot honestly say if people tune their systems by underlying physics or by the sonic consequences of that. But I agree that understanding what is happening electrically is interesting and can be used in explanation in what we hear.
Looking back to the entry by Richard Austin where a dealer demonstrated a power conditioner that improved the sound of one device, but not another, we can deduce that cables can be chosen by dealers (or owners) to correct the sound defects of a particular piece of equipment. We can equally deduce that those same interconnects may make no difference (or an negative difference) to another piece of equipment.
Herein lays the rub of this thread; that which makes a positive difference in one set up may cause a negative or negligible difference in another and by the nature of this website comes to us from anecdotal experience. Although the tone of my replies so far on this thread would suggest I believe it is all snake oil and to now say otherwise here is hypocritical, I am certain there are experts on this forum who have discussed observations/findings in this and other threads that might be totally appropriate to the OP query.
For example, I think it was back in March that Shakti noted that an Onyx-bodied Koetsu cartridge, that had neither the platinum magnets or the diamond cantilever , that he listened to sounded great, like the sound of those Koetsu cartridges he initially fell in love with. We also know that before platinum/diamond, the Koetsu only differed in price (and sound?) by what the body was made from (the insides were identical). Certainly there is useful information here. No, not that the sound of your hi-fi would improve if the components were encased in Onyx, but that if you are looking for that classic Koetsu sound you might be wise to audition pre-platinum magnet and diamond cantilevered cartridges before buying.
In response to my belief, referred to in my first paragraph, that some types of insulation on interconnects will turn the interconnect into a low-pass filter; I purchased Dulund wire which insulates with woven silk and oil. Does such not behave as a low-pass filter, Is it the best option? I don’t know, but it sounds great to me (totally anecdotal I know, but some here know the truth).
The OP asks if all things affect sound, I don’t know the answer to that question but I do believe that the more things between source and speaker the more the sound is adversely affected. What was the saying used to describe the best amplifier, “ a straight wire with gain”? Does this concept explain why, to many, SET’s sound better than pentodes and push-pull circuits?
I think that the experts on this forum (and I am certainly not one), could be able to converse amongst themselves and work out what designs/materials would, in fact, make the biggest difference to this hobby for the benefit of all.