A very illuminating piece, Mike. It's interesting to hear so many authorial voices from different eras singing from the same songsheet.
I think this idea of not really knowing what the ideas are until they are set down in words also ties in with the inadequacies of GPTs.
They only see and base their predictive output on the words themselves, not the sublinguistic urges and feelings that link together and generate the words. There's a inevitable lack of that internal dialectic between what a writer conceptually wants to say, and the 'physical' words that express and shape that concept.
It's maybe a little like dry stone walling. The expert waller is building not just with the stones, but with the empty spaces between the stones, and their points of friction and contact. Selecting the next stone to accommodate not only the positive space of what came before, but the negative space that must lie in-between.
The wall will ultimately follow the intended layout, but its detailed composition and outward appearance will only come into being through the act of creation.