Science isn't opinion, the dielectric properties of all popular insulators are well documented as well as easily measured.
What is debatable is there a "real world" impact and this is dependent on "real wold conditions" which are not defined more precisely here
So saying "No audible effect" is only valid if the conditions are defined. otherwise one could falsely assume under all conditions.
Here is a "measurement" i made, showing another related and glossed over effect of cables.
Some dielectric materials seems to be triboelectric or have piezoelectric effect.
Actually im not sure but matter of fact is the tested Cat5E is microphonic.
Rubbing, bending and hitting the cable makes Noise.
Recognized this problem under real world condition in my real world.
Years later someone told me taht's impossible... but i was able to recreate it with another cable
https://soundcloud.com/lambda-9%2Fcat5e
most circumstances, that's pretty close to the truth. More importantly, it doesn't take a huge amounts of engineering skill to take the concept of a rusty paperclip and add the elements that gives you a close to ideal RCA cable, at least for all practical purposes.
But choosing the not challenging circumstances than seems kind of pointless to me.
At least in Germany its not uncommon to have some sort of ground loop issues and or a view mV Noise between Antenna Ground, CableTV Ground, PE and N
People carelessly connecting there TV,PC ,radio and what not to there AVReceiver or Preamp and then wonder why the turntable is humming...
For me a little bit of common mode noise current therefore does not seem to be a like a totally made up test.
Under this conditions it's maybe possible measure a difference between the 1,95$ 5m RCA cabel and some decent quality 10$ cable.
But the 2000$ cable will still be pointless because as we all know. it is...
and establishing that they do NOT deserve any benefit of the doubt.
it seems entirely possibly to me to give it the benefit of the doubt and anyways show that its Snake-oil