I will go further and say I dont even think it has anything to do with jitter or timing. The changes in network equipment and cables, which are audible, are all about the ground noise, and also the ultra high frequency noise from oscillators and fast switching network chips riding down the connection path into the analog part of the audio system. And galvanic isolation does nothing to block this high frequency noise, it only helps on a certain part of the noise spectrum.
None of the above effects the data packet transfer, which works as per spec, regardless if ground noise and high frequency noise is very high or very low.
None of the above effects the data packet transfer, which works as per spec, regardless if ground noise and high frequency noise is very high or very low.