From my EE days:
Copper I think is something like 97% conductive as Silver, which lets say is 100%.
However, this is variable on temperature too, freeze the copper down to -50C and Silver down to -50C, they get more conductive. Are we now going to thermally freeze our speaker wires to super conductivity, so impedance goes to zero?
Hey guys I have a novel idea, lets sell super conductivity wires for $100k a pop, and with it, sell $500/month 1L liquid nitrogen so idiots have to subscribe to our plan and every month you have to refil your liquid nitrogen tank to reduce harshness so that you wires have to be in a super conductive state.
The irony is that, the two ends are not super conductive, so you're still pretty much using regular wire