Semiconductors conduct less than most metals. They aren't made for power transmission, they're made for logic (0s and 1s). Superconductors are doubtful to work because they literally have zero resistance, which means if you apply a charge to the superconductor and there is nothing to drain that charge, it will stay charged until something drains it, even just a wire stays charged. Superconductors are for power transmission. If low resistance was key in signal sending then the wires would be as thick as possible everywhere, and they aren't. Going from copper to silver isn't going to do anything but get more power to the destination, it's not going to cure problems like noise. The cheap RCA cables, and such like that, are proven time and again to be no worse in quality than the expensive cables. Even for video they are fine, and video is something to easily spot degradation.
