Well, I apologize. I overestimated just how much Nuke and others know about how CDs work at the hardware level. You're looking at it from a higher level, like Newtonian physics vs. quantum mechanics.
Transferring anything, digital or analog, to another media is never perfect, and reading it is never perfect. With CDs, we're talking about transfering the data to a media using a geometric shape and the mechanical manufacturing transfer process is not error free. It's not like copying non-audio data machine to machine.
The glass master is used to make a metal stamper to press CDs. The glass master is not a perfect reproduction, but close enough. Yes, it too has errors, but the analog result is imperceptable to the human ear - they happen too fast. However, every step down the chain will introduce more imperfections.
Those CDs are read by analog mechanisms and digitized by gating. The raw error rate is surprisingly high and both encoding and error correction are used on all CDs to bring it to a manageable level. A data disc has an extra layer of error correcting code (ECC) which uses about 13% of the space; that is not used for audio, so the player provides error concealment or suppression circuitry to reduce the effects of misreading.
Audio CDs are read at 1x speed, so there isn't any time to go back and check if that 0 was really a zero, or the 1 was really a one, like is done on data discs. If you have a lot of things looking like 0.1 or 0.2, or 0.9 or 0.8, it's manageable. But when you get things looking like 0.4 or 0.6 hundreds of times during that unique read, those are hidden from you and massaged at the analog stage so you won't notice them much. But they are there.
A fast-spinning disc being read by a moving laser will always exhibit read errors. They are common and frequent on pressed and non-pressed CDs. Gaussian effect increases the read errors and it should be obvious that greater material clarity of the suface will reduce read errors since brightness and darkness across the read path is wider.
When you extract digital data through DAE or in raw form from a CD or VCD, stuff happens. All things being equal (format), the faster you run DAE, the greater the number of ticks and pops - bit errors - you will encounter.
If you think all subsequent digital copies are exact, then try making copies of copies of copies of CD-Rs on different drives with different writing software. In theory, it's just zeros and ones, right? The data will be there, no doubt. But in practice, the reading errors of that data at 1x speed will compound until degradation is evident to the ear as a reduction of sound brilliance.
For example, here are differences at the analog line output between a pressed CD and a CD-R. This data is directly from the redbook people - Philips. They should be the same, if digital is digital, right?
Line Out
Amplitude Linearity
On pressed CD: 1.5 dB (20 Hz - 20 kHz)
recordable CD: 2.5 dB (20 Hz - 16 kHz)
S/N-ratio
On pressed CD: 81 dB (84 dB A-wtg)
recordable CD: 80 dB (82 dB A-wtg)
Total Harmonic Distortion + Noise
On pressed CD: 65 dB (1kHz)
recordable CD: 55 dB (1kHz)
Channel separation min.
On pressed CD: 70 dB (20 kHz) min.
recordable CD: 65 dB (16 kHz)
Those numbers are pretty good, but why don't they match? Why is CD-R playback inferior to that from a pressed disc if digital copying is exact?
Well, How about errors during data impression to imperfect media?
A glass CD, manufactured with fewer errors than an industry-standard pressed CD, will have less error correction being performed by the variety of drives out there and provide better archival quality of the data for subsequent copying.
I'm done. For those who are so darn sure I'm spouting nonsense, perhaps you don't know enough to even know the difference?
Cheers
