I'd probably lose this bet....

Let's not forget inductance of straight wire. For instance 20' (counting both ways) of gauge 14 copper speaker wire has inductance of 12.64uH equal to reactance of 1.6ohm at 20kHz.

I once suggested a bet that I would identify 20 out of 20 different interconnects,if listened to them in my system,and allowed to take notes-as I do not trust my short term memory any more-for how long has that been the case?
There was one character in particular who doubted my ability.When I realized that this wager meant having uncouth people in my apartment,I said -what the hell and dispensed with the circus.

Kijanki, yes, a long cable like that can thus be seen by the speaker as a higher output impedance of the amplifier resulting in a lowered damping factor. As you point out, this likely has more effect at high frequencies, but if we are talking about hearing differences between cable, its not rocket science (although there is math :)...) to see that there could be an audible, measurable and repeatable difference.

Atmasphere, First speaker cable I had was thick stranded Monster cable (clear insulation). I found later that it is possibly the worst type of cable because skin effect starts in copper at 20kHz at gauge 18 causing smearing but also because same skin effect causes current to constantly jump from strand to strand in order to stay on the outside (lower resistance path) crossing each time impurities that reside on the surface (copper oxide is a semiconductor). When I got Audioquest Indigo I noticed that highs became much stronger, open, faster. This cable was decent for class AB amp but sounded thin in lower midrange with lean sounding class D amp. I replaced it with Acoustic Zen Satori that not only fixed this problem and added overall speed and clarity but also added pleasant "silkiness" to voices. Can anybody define "silkiness" in terms of RLC?

Not many would believe that power to speakers is not really delivered thru the wire but on the outside of the wire. It gets even more complicated with coax interconnect where energy is delivered only thru dielectric (there is no energy delivered thru wire itself). I also suspect that we still don't know everything about electric current (that could explain "silkiness")

It might be interesting to measure the Characteristic Impedances of those cables and see how that interacts with the impedance of your speakers in the vocal range.