Greetings. Other than updating my findings above with several edits over the past couple of weeks, I have now completed a 33-page white paper (research paper) and published it online at my website.
I am not allowed to post a link given my post count here is so very low, but if anyone would like an inventory of modern rigging knives, fixed-blade and folding, then this PDF eBook is available for free (and will remain that way). It is the very first link cited when one searches Google with "nautical rigging knife market." Title: "Nautical Rigging Knives: A Guide to the Market."
The investigation started with my post above a couple weeks ago, and it continues the same line of thought - five features, and nothing more, would bring folding knives into a new realm of sufficiency. I've tried to keep the analysis completely neutral, but whether I succeeded or not, I hope the study is helpful to someone somewhere. Thank you for your responses. -Vince