We are very fortunate to be able to participate in a robust and respectful discussion, involving so many people from different backgrounds, locations and experiences.
...and all out of LOVE for the music!!!

While many scientific/mathematical facts have been offered in this thread, I believe it is important to remember that, at the end of the day, the scientific/mathematical theories/rules/descriptions are snippets of information by which we seek to understand complex real-world phenomena.
This is not to say that the theories are false or even 'lacking' in themselves, but rather, that we must take caution when claiming that the 'snippets' themselves can completely explain or deny the existence of real-world effects; which are usually incredibly complex and multi-faceted.
In this sense, from a scientific perspective, I believe it would be very worthwhile to investigate the mechanisms by which dithered audio can possibly affect human perception,
especially at seemingly 'imperceptible' levels.
For example, perhaps 'level' (i.e. amplitude), viewed in isolation, is not the main driving factor in the 'perceived' result for dithered audio.
Personally, I find fascinating the degree of consistency in the descriptions of dithered vs non-dithered audio (at say, 24 bit), from those who claim to perceive (at times) a difference between the two. (Note: this is not to imply that every person does, can or
should perceive these differences, or perceive them in the same way).
One possible conclusion is, of course, "it's all in their head/s", or eyes, or wallets, or 'forum hysteria'...
There could, however, be other conclusions.
That's basically the history of Science itself. Sometimes the solutions to such situations are remarkably simple, just not well understood at a given point in time.
And we can all still make great music, irrespective of those conclusions!