I have a feeling that a lot of what Docile is doing is working off of established slavefic tropes. It's entirely possible that The Sardonyx Net helped establish some of those tropes (I remember reading it and thinking "An actual publishing house published a slavefic? In the eighties?") although I doubt many of the people writing slavefic today have read it.

Certainly, from Brave New World on, if not before, there is a history in science fiction of oppressive regimes keeping people in line with drugs.

(Disclaimer: I haven't read a whole lot of slavefic, so I am not the most knowledgeable about its tropes.)