Theoretical question about how CD's work

Here’s some really bad news, especially if you purchase CDs from eBay. For anyone concerned about dynamic range on your CDs, you will find generally that CDs listed for sale are the compressed reissues. Usually, not always, the original CDs that came out in the 80s or 90s are the most uncompressed versions. This is a generalization, and I’m referring to classic rock CDs here. When an original CD of a particular album does come up for sale, especially if it’s a Japanese or German import, the price is double or triple.The trend is not your friend. Apparently everybody and his brother are dumping crappy overly compressed CDs. Which in a weird way is refreshing, inasmuch as your humble scribe is not the only person who eschews compressed CDs. 

Someone who actually knows what they're talking about, ie NOT kosst_amojan :

Bits is bits? 
Although CD manufacturing appears to be a straightforward process of stamping inviolate ones and zeros into a plastic disc, these manufacturing techniques introduce analog-like variations in the quality of the HF signal read from the disc. 

Because the HF signal recovered from the finished CD is created by the tiny pit-and-land structures, it follows that any changes in pit shape will affect the HF signal. Well-formed pits produce a good-looking HF signal; poor pit geometry creates a poor-quality HF signal. 

A clean HF signal is essential not only to low error rates and good tracking ability, but also to sound quality. Although the HF signal undergoes significant processing before the raw audio data and timing clock are recovered, many digital designers agree that the HF signal's shape and quality affect how the disc sounds. Some high-end transports even have circuits to clean up the HF signal before it's sent to the decoding electronics. 

That the HF signal's quality affects the sound is suggested by many examples of audible differences where there should be none. In 1986, Doug Sax (footnote 4) first alerted me that CDs made from the same CD master tape, but pressed in different factories, sound different. Doug routinely buys CDs of records he's mastered and compares them to the original CD master tape from which the CD was made. He has found a huge variability in sound quality between different pressing plants—some plants produce discs that sound very similar to the original; others make discs that sound dreadful. The only difference is in the manufacturing process. Indeed, engineer Bob Katz's experience, described in the companion piece to this article, further suggests that, although the binary 1s and 0s on two CDs may be the same, it doesn't necessarily follow that the discs will sound the same.

So its Doug Sax, who we're pretty sure can hear a difference, vs kosst_amojan, who we aren't sure can hear at all. This by the way is from the Stereophile article, The Analog Compact Disc. The key word in case you missed it kosst is analog, not digital, and it ain't no typo. It would seem you are once again way, way, WAY off base. https://www.stereophile.com/content/analog-compact-disc-page-2

There are quite a few reasons why the same issue CD of a recording from different CD manufacturing plants sound different on the same CD player.

The accuracy of the process of laying down the bits and lands on the metal master.

The accuracy of producing the actual CDs from the metal master. The edges/transitions between pits and lands must be perfectly clean and correct with respect to timing (lengths of pits and lengths of lands).

Differences in the inks used for the CD label. Some inks may be more ferrous. Also if the colors of the inks are different that would influence the sound, too.

The thickness of the CD can influence the sound since a thicker CD will be stiffer and not flutter as much during play as a thinner one.

The transparency/purity of the polycarbonate layer. The nominal transparency of polycarbonate is actually only about 91%. SHM-CDs employ a more transparent material for the clear layer. Hence Super High-performance Material (SHM). Less transparency, more laser light scattering.

The purity and composition of the metal layer. Some metals and alloys have higher reflectivity for infrared light than others.

The variation in roundness of the CD. We know that out-of-round CDs flutter and flop around more than CDs that are perfectly round, causing mis-tracking.