"Since one polarity is often superior." No it's not. They're identical. The CD or LP can be recorded in either "normal" or "inverted" polarity* and played back in either. It helps if the playback matches the recording, but because most speakers are not polarity-coherent (with minimal or no crossovers) anyway, it only makes much of an audible difference on the ones that are. This subject is a hardy perennial, but that doesn't seem to make for much clarity about it.
* And many are recorded in mixed polarity. I have discs where I can bring the vocalist forward or put him/her in the background depending on where the polarity switch is set on my preamp.
* And many are recorded in mixed polarity. I have discs where I can bring the vocalist forward or put him/her in the background depending on where the polarity switch is set on my preamp.