If this thread is simply and truly palaver, res ipsa loquitur so Im not sure how any meaningful inferences could be drawn from it. :confused:
Jonathan, the quality of the facsimiles is high. Printing of this quality is not cheap. To stop press, swap plates for a few illustrations, then get the inking and registration to the point where the printing is of the desired quality takes time, and thus money. However, if there are differences in the illustrations between some copies and if those differences existed on the same printed sheets, maybe some economies of scale could have been accomplished. But that all depends on how the sheets were printed and quired. My copy is bound so tightly that I cant really tell how the sheets were printed (i.e., 2 up, 4 up, 8 up, etc.) nor how they were gathered (i.e., whether the book is a folio, quarto, octavo, octavo in 4's, octavo in 2s, etc.), nor if the leaves for pp. 39 and 47 are conjugate.
Of course, this still all may be grist for the fantasy mill... .