Adding to my list of probably wrong predictions about where a current Star Trek show is going (most recently, for Discovery, those would include that the Kelpiens and the Ba’ul are different stages of the same species and that Control was the genesis of the Borg)….
Spoilers for episodes two and three of Picard follow, but probably not for anything beyond that, because I’m usually wrong about these things. :)
Episode two introduced us to the Zhat Vash, the “double secret” version of the Tal Shiar, the Romulan secret police. It seems that the Zhat Vash “was motivated by hate, fear and pure unassuageable loathing for artificial intelligence, including androids, AIs, and other forms of synthetic life, which they attempted to seek out and destroy” (quoted from the Memory Alpha Zhat Vash page).
In episode three, we see a number of Romulan XBs (ex-Borg…though using a two-syllable acronym for a two-syllable phrase seems…odd…). Apparently, and as pointed out in the most recent Shuttle Pod podcast (which is what sparked this chain of thought), these are the only Romulans known to have been assimilated, and every single one of them is exhibiting difficulty regaining even near-normal functionality (I don’t immediately remember the term used in the episode). Soji seems to believe that their state “might be a consequence of the assimilation of the Shaenor, the last vessel which the Cube encountered before its submatrix collapse” (quoted from the “Continuity” section of the Memory Alpha page for this episode).
So, wild theory time:
What if at some point in the past, either shortly after the first Romulans left Vulcan, or at some point not long afterwards, some event occurred that led the Romulans of the time to incorporate some form of AI into their biological makeup? Then, at some later date, a societal shift happened that led them to decide not just that this shouldn’t have happened, but that the decision to do so was flawed from the start, and shouldn’t be admitted or spoken of again. However, because it was performed at a biological level, it couldn’t simply be excised from their genetic makeup.
So, ever since then, there’s been a proscription against research into AI (and, by extension, any form of synthetic life), due to the eventual possibility of discovering the Romulans’ deep shame that they felt they couldn’t overcome whatever event started them on that path without cybernetic assistance. Only a small cabal–the Zhat Vash–still knows the truth of the matter, and are charged with policing and enforcing the stricture against such research. Over time, this has morphed into essentially a secret society with a near-religious fervor against any form of AI or synthetic life.
However, the Borg, being a highly adapted collective of species that makes heavy use of AI, cybernetics, and biosynthetic technologies in their quest for assimilated perfection, cause problems. Because when Romulans are assimilated, something about the process awakens or interfaces with whatever synthetic/AI remnants still exist in their biology, which is both what triggers the Borg Cube’s submatrix collapse and prevents the recovered Romulan XBs from reintegrating after their recovery.
So now the Zhat Vash (possibly through the Tal Shiar, possibly on their own) are doing everything they can to contain the issue and ensure that the shameful secret of their ancestor’s reliance upon AI stays hidden.
Sure, it’s a long shot theory, and there are problems. As Memory Alpha notes (also in the “Continuity” section of the page for episode two), there have been a few instances of other Romulans encountering the Borg. Voyager encountered a Romulan Borg drone named Orum who had been severed from the Collective, and a note on Orum’s Memory Alpha page points out that in the TNG episode “The Neutral Zone”, it was mentioned that “Romulan colonies were scooped out from the surfaces of planets by the Borg”; it seems reasonable to assume that any Romulans in those colonies would have been assimilated rather than simply killed.
However, perhaps the Borg were able to account for whatever weirdnesses this theoretical Romulan bio-AI introduced at the time of Orum’s assimilation because he was the only Romulan assimilated at that time. Additionally, as Orum was part of a group of Borg drones all severed from the collective at the same time and wasn’t going through whatever reclamation process the current Romulans are using in their Artifact research, perhaps that let him avoid whatever issues these recovered Romulans are facing. As for the Romulans assumedly assimilated from the destroyed colonies, we (to our knowledge) never encountered them; it’s entirely possible that their assimilation did cause problems, and so the Borg simply severed any affected Cubes from the Collective at that time, and we’ve simply never run across evidence of that happening.
Of course, it’s not Star Trek with a few fun inconsistencies worked around through creative retconning, so who knows? Maybe it could work?
As I said at the beginning, of course, I don’t have a very good track record for making these guesses. But maybe this will be my time to shine!