Art Dudley is such a good writer, he's enjoyable to read just for the writing. He really puts the music itself ahead of the "sound" of music, faulting gear that itself doesn't. It's a subtle distinction, since music is, after all, sound first.
But the idea is, Gordon Holt (and Harry Pearson, for that matter) critiqued hi-fi in terms related as much to photography, a static medium, as to music, which is not. Art's point of view is that the temporal performance of a component (it's timing, forward momentum, etc.) is more important than it's static sound (accurate timbre, lack of coloration, transparency, etc.). And the physical dimension---imaging---is for him a very low priority. But the "size" of instruments---the bigness of a grand piano, the smallness of a mandolin and fiddle---Art refers to that as scale, IS important to him.