On the whole I'd agree.  I think that two electrically identical (or very similar) cables can certainly not be distinguished and all those standing prizes of $10K or whatever it is for distinguishing two cables in a DBT stipulate the cables must be electrically identical.

I would guess though that most cables are pretty similar in LRC terms, ergo, they are all probably indistinguishable.

I think that you'd need pretty massive variations in LRC for changes to be audible.  TBH I think it's far more likely that sockets and connectors/plugs etc can make a much bigger difference than the cable they're attached to.  There's a lot to be said for good, clean junctions where metal meets metal in a circuit, not to mention potential electrolysis where there's a junction between two different metals (which could accellerate corrosion of the contacts).

Michael.