[1] I wasn't talking about resolution. Dynamic range is a separate subject.
[2] With digital imaging, resolution is the number of pixels or dots in a given area. ... There is no such thing as infinite resolution: if you were able to go up close to a billboard (which can be as little as 20dpi), you would start seeing softness before just seeing individual points.
[3] Also, content creators need larger dynamic range of their source files to be able to pull up detail in shadows or recover blown highlights (especially when converting HDR images to monitor color spaces). Try post processing an image that doesn't have enough DR, and you'll either see noise or black splotches in shadows as well as complete white splotches in highlights.
[4] I realize there is not a 1:1 comparison of digital sound reproduction to image reproduction. However, it is valid to understand respective technology and see what analogies there are.
It's possible I have misinterpreted your post and am therefore going to inadvertently misrepresent it. If that's the case, I apologise in advance but it's still worthwhile as it goes to the heart of the OP:
1. In the case of digital audio, resolution and dynamic range are effectively exactly the same thing.
2. This really is a fundamental difference between digital imaging and digital audio! With digital imaging (as I understand it) we have a fixed output, an image is recreated using a fixed number pixels which when recreated correspond to (for example) a fixed number of LEDs. The more pixels/LEDs the higher the resolution but obviously we cannot have an infinite number of pixels, as that would require an infinite amount of data, and we cannot have an infinite number of LEDs, as that's a physical impossibility and therefore with digital imaging, as you say, "There's no such thing as infinite resolution", the only question is how many points (pixels/LEDs) we have and under what conditions that number exceeds the capabilities of the human eye. This is completely different to how digital audio works, the analogue signal output reconstructed from digital audio data does not have ANY fixed points, is not reproduced by a finite array of say LEDs and having more fixed data points (pixels) does not have any effect on resolution. Therefore, there IS "such a thing as infinite resolution" in digital audio, in fact, the whole principle of digital audio is based on infinite resolution (Shannon/Nyquist)!
Despite my ignorance of digital imaging, I'll attempt an analogy: Let's say we have a perfect circle which we want to capture and reproduce as a display graphic. We can capture/measure various points on the circumference of our circle as pixel data and then output that pixel data to say LEDs. The more pixels and corresponding LEDs we have, the more accurate (higher resolution) our reproduced circle will be. There is another way though, we can measure just 2 points on the circumference of our circle, which we store as data, mathematically define a perfect circle that bisects these two points and we now have infinite resolution! As I understand it, these two different methods define raster graphics and vector graphics respectively and digital audio is analogous with vector graphics, not raster graphics. This analogy fails in the final step though, because all displays have a fixed/finite number of LEDs, so our vector graphic has to be rasterised accordingly and we're stuck with that finite resolution defined by the number/density of LEDs. While with sound/audio reproduction we do not have LEDs (or any audio equivalent), we can in effect directly output that vector graphic without rasterisation, thereby maintaining infinite resolution! The limiting factor with sound capture and reproduction is therefore not digital audio but the laws of physics pertaining to the analogue input and output signals (EG. Thermal noise and transducer inefficiency).
3. Again, this is a massive difference between digital audio and digital imaging. 32bit float audio post processing (mixing) has been around for 20+ years which theoretically could encode a dynamic range of 1673dB. However, as a sound wave is the compression and rarefaction (variations in pressure) of air molecules, at 194dB the rarefaction portion of the wave would be a total vacuum and as we can't have more than a total vacuum, we can never have a sound wave greater than 194dB, beyond that point we can only have a shock wave. Being even more silly, a shock wave of 1100dB would so massively compress the air molecules that a (5kg mass) black hole would form! In digital audio, our processing environment massively exceeds what can ever actually exist in the real world, let alone what transducers or human senses are capable of.
4. In theory I would agree but in practice, as they're quite different, complex technologies, it's difficult to understand both of them and therefore analogies between them tend to be either invalid or only valid up to a point (and are then invalid again). So even in the latter case, when an analogy might be a useful aid to explaining/understanding a specific aspect of digital audio, it's more than likely to lead to a misunderstanding of other aspects and of digital audio as a whole.
[1] We haven't reached the DR limits of vision with imaging, and
[1a] there are very different applications where resolution comes into play. A 46 mega pixel camera is over-kill for an image that gets scaled down to say a 1024 web image. But a person may still want that original size for making a high quality print at a large size.
[2] While imaging still has room for improvement, I would agree that we've reached the limits of fidelity with audio in relation to human perception....and I leave it to others who may want to expose themselves to sound peaks over 100dB or want to argue what processing method (in relation to 1bit to 16bit to 24bit) is "best".
1. This is largely addressed by my point 3 above, we exceeded the DR limits of hearing with digital audio decades ago and 20+ years ago exceeded what can even be reproduced according to the laws of physics.
1a. There's no analogy for this with audio!
2. I would point out that sound peaks and dynamic range (and therefore number of bits) are unrelated. In the real world of music gigs, an audience member might get peak levels of 120dB at an exceptionally loud EDM/rock/pop gig (if they're close to the speakers) but a dynamic range of only 40dB, for which 8 bits or so would be sufficient. While at a large, loud symphony gig, sitting close to the orchestra you might experience 96dB or so but a dynamic range of nearly 60dB, for which 11bits or so would be sufficient. From the perspective of an audience member, there is no real world music circumstance that exceeds (or even comes close to) the dynamic range of which 16bit is capable. In other words, 16bit digital audio already exceeds what actually exists in the real world (of music gigs), regardless of human perception!
G