I do think audiophiles trump musicians when it comes to superstitions. Just recently found out there’s a market for cables costing hundreds of euro’s to interface hi-fi components, with lush descriptions of the soundstage afforded by such cables. Ignoring the fact any record one listens to will have its sound passed through 20 euro cables at some point in its production.
I can see something like this being a part of the audiophile attraction to these types of components: that every time the owner adds a new set of magic interconnect cables, magic power cables, or whatever, they imaging that they hear an improvement. In the end, they have a lot of themselves invested in their "rig", as they call them, and so find it easy to hear virtues that aren't really there.
I'm hoping these blokes never crack open the amp to look at the plain old PVC-insulated wiring within. And don't tell them the oil-in-paper caps are fading over time. Ditto with the carbon resistors.
Meanwhile, humidity of the air and barometric pressure has a measurable affect on the sound of paper-cone speakers. How long before an "audiophile" barometric chamber is marketed?
The weakest link always has an effect, as you mention. To some musicians, this is the effect. I.E. Hendrix preferring cheap coily-cables which rolled off the high-end on his Strat/Marshall combination nicely. Now coil cables are a premium.
[1] https://www.google.com/search?q=audiophile+coat+hanger+test&...