I've asked my substantial question as a 'question', but just wanted to say here how much I enjoyed reading this. It's a fascinating reminder of older attempts to improve scholarly communication, and a reminder that some interest groups are more powerful than others.

It helps me, in my historical work on the Royal Society's journals, get a better picture of the changing context of the 1960s, when there seem to have been so many concerns about improving scholarly communication and academic publishing. There were some grand hopes for the possibility of microfilm back then, too! (For an on-demand ordering service based around central holdings of microfilmed journals: brief mention in Gitelman's Paper Knowledge; and the subject of Matts Lindstrom's recent Stockholm PhD thesis - in Swedish, so far...)

As I said in my Q, I am surprised that the societies in your story felt threatened, rather than encouraging. It surprises me that they didn't see their own editorial processes as adding sufficient value to a pre-print.