Wire properties can certainly affect digital pulse characteristics. But, up to the point where a data "one" can be misinterpreted as a "zero" pulse characteristics don't affect the information which goes into the D/A converter.
So I don't find it "mysterious" at all that various cables sound the same. The mystery is why some folk think they sound different.
The only possibile explantion is increased jitter that you can get from passing signals between devices. I agree about the "ones and zeros" - these should be recognized properly and completely (so the bits are the same).
In this case, it may not be the fault of the cable but the way in which the components clock timing interacts.
Perhaps a device with superior PLL & timing/receiver ciruitry might sound the same with any cable when connected to a digital source (even a relatively jittery one).
Perhaps a device with poor PLL & timing/receiver ciruitry might sound different (more or less jitter depending on characteristics of signal received)...
