Most of these threads are a collection of beliefs with not one line of scientific demonstration. It is quite interesting, however that Paul Frindle demonstrates that operating a TOO LOW level may introduce problems.
And again: Please remember, the question was: "Is it really necessary in digital to print all the way up to 0dBfs to maximize your word length? Are amplitude and word length in digital truly related in that way?".
There's only one answer to that: Yes
Because the question is exactly the same as: "Is it really necessary in analog to print all the way up to maximize S/N ratio? Are amplitude and S/N truly related in that way?". Again, yes.
I'm not saying that there won't be any problems, because there will be distortion, but the QUESTION doesn't mention distortion. To a unidimensional question, I bring a unidimensional answer. If distortion had been mentioned in the question I would have said that S/N and THD are mutually exclusive. If the question was about quality, I would mention the compromise between wordlength and loss of headroom.
And I don't really need to read any "digital for dummies" book after 37 years of product development...