Audio tracks are not files on disc, so technically it is not easy or even possible with some equipment to accurately reconstruct them back into files.
They are just streams of data with some metadata that can be used to indicate to the player which track is playing at which time.
This metadata may come out with the S/PDIF stream or not, and even if it does, receiving it with a PC may require an advanced professional audio interface card, as standard sound cards usually don't receive this metadata and they may not even bit-accurately receive the audio if some internal resampling is done to sync the audio with the receiver master clock.
As copying tracks to audio files was not initially possible on early CD drives, on the drives it was possible it was usually highly inaccurate. The so-called CD ripping programs use algorithms to extract the audio by reading it multiple times in chunks of data that overlap and then they discard the identical parts and only add the new parts into a file, which may or may not produce an identical disc when the audio files are burned back again as an audio disc.