Well, Guinan's actual line from "Q Who" is, "They're made up of organic and artificial life which has been developing for thousands of centuries." Which is... wow. Kind of incoherent. It's hard to see a clear, definitive way to parse that. And given that Guinan is a refugee from the Delta Quadrant who wasn't even present when the Borg destroyed her world but only learned about them secondhand, I don't think she qualifies as an expert whose statements must be stipulated as fact. That rather confusing sentence of hers could've simply been wrong.
First - "incoherent"? What exactly is incoherent about the statement, Christopher?
It's actually pretty straightforward.
Well, for one thing, it isn't grammatically consistent. There are evidently two subjects, "organic [life] and artificial life," but it has a singular verb, "has been." So which is she referring to? If she's referring to them both collectively, that isn't very informative given that organic life has, obviously, been developing for
billions of years. If she intended to say that two different forms of life have been developing
together for thousands of centuries, or merged together that long ago, she could've chosen a clearer way of saying it.
And "made up of organic and artificial life" can be interpreted any number of ways. First off, how do you define "artificial life?" Taken literally, that phrase would refer to biological organisms that were created by intelligent beings. "Artificial" doesn't mean "not organic," it means "made by craft," manufactured by people. We can excuse a little inaccuracy and grant that in vernacular, "artificial life" probably refers to inorganic technology which is self-replicating and mimics the behavior of living things. Or, in the case of Data (a so-called "artificial life form"), technology which possesses consciousness and thus tends to be characterized as "alive" by a sloppy definition of the term. (I always hated that drink-mix commercial from my childhood where the kids exclaim, "The flowers are alive!" when the flowers turn out to have faces and fangs and try to eat them.
All flowers are alive, you idiot children!!)
So yeah, in retrospect, clearly it was meant to say that the Borg are a hybrid of organic life and self-replicating technology, and was probably meant to say that the hybridization originated in at least its most primitive stage thousands of centuries ago. But it's a very poorly phrased way of putting that across, so that grants us some ambiguity even if it wasn't intended to.
Second - yes, Guinan was not present when her homeworld was destroyed by the borg. She knew only 'bits and pieces' from her people.
But she, the listener, was certain these 'bits and pieces' were accurate - and expressed herself consequently.
If anyone can judge correctly the veracity of such information, Guinan can.
At most, she could determine whether her sources
believed that what they said was true. She would have no way of knowing whether those sources' beliefs corresponded to objective fact. For thousands of years, most educated humans sincerely believed that the Sun revolved around the Earth. If someone with infallible lie-detection ability asked a bunch of pre-Copernican scholars whether the Earth circled the Sun, they would all say "no" and the listener would be convinced they were being as honest as possible. But they would still have been completely wrong, because belief is one thing and objective fact is a completely different thing.
After all, it's not like the people Guinan spoke to would've been immortals who'd actually
witnessed the creation of the Borg firsthand. Anything they told her, no matter how sincerely they believed it, would've been hearsay countless generations removed. Or maybe even guesswork. After all, it's unlikely that many witnesses to the early days of the Borg would've survived to tell anyone what had happened. It's just not realistic to expect that
anyone short of Q's level of perception would have direct, reliable information about the Borg's origins. And Q didn't say anything about how or when they came into being; only Guinan did.
Also, as already said, as per the scenarists' intent, her statements are to be taken as 'fact': her character has ALWAYS been a reliable source of information.
But the scenarists' intent in "Dragon's Teeth" is blatantly contradictory. So since we only have those two references, they cancel out where intent is concerned.
Star Trek is full of cases where one writer has intended one thing to be true and a later writer has grossly contradicted it. Hell, most of the stuff that was intended to be true about the Borg in "Q Who" -- that they're incubated from infancy rather than assimilated, that they're only interested in technology rather than people, that their ships are totally decentralized without any distinct engines or computer cores or weapons nodes, that you can't get life-form readings from drones, etc. -- ended up being blatantly contradicted by later Borg episodes (and movie). Essentially everything "Q Who" told us about the Borg was later decided to be "wrong" or at least incomplete. The producers of later Borg stories never hesitated to contradict what "Q Who" asserted or intended, so why should this factoid -- which was also later contradicted -- be any different?
The Vaadwaur's exploration/sphere of influence extended only in the relatively small region of the delta quadrant where their subspace channels network existed.
"Dragon's Teeth" happened in the early 6th season. By that point,
Voyager had made the following jumps through space: 9500 light-years courtesy of Kes, 2500 ly through the Malon vortex, 10,000 ly by quantum slipstream, 20,000 ly by Borg transwarp coil, and another 200 ly through the Vaadwaur corridors (
Star Charts mistakenly puts the Vaadwaur homeworld before the corridor instead of after). And that's in addition to the over 2000 ly they'd covered through normal space according to
Star Charts's estimates. So the Vaadwaur homeworld was something like 45,000 light-years from the Talaxian homeworld -- and yet the Vaadwaur were familiar with the Talaxians and had visited their homeworld. So we know that the Vaadwaur corridors spanned a distance equal to nearly half the diameter of the Milky Way Galaxy, or nearly the entire radius of the Delta Quadrant. That's not "relatively small," that's mind-bogglingly immense.
7 of 9's affirmation about the borg's memories of that era being fragmentary actually suports the theory that, in the recent past, the borg suffered something akin to a cerebral stroke - as a consequence of assimilating the Sedin-descended collective and fundamentally changing the hive mind?
Other than a stroke extending through the entirety of the collective, there's no way to explain loss of memories by the borg - between its famed redundancy and the fact that a single ship retains all its memories (look how much 7 of 9, a mere drone, retained of this racial memory).
There are certainly other ways. For instance, there could've been some powerful enemy that developed a computer virus or energy weapon that disrupted the Borg's memories. That could be what knocked them back to the small number of systems they occupied in the 15th century. Or it could be quite simply that the Borg were still a new, developing civilization at that point and hadn't yet evolved into their modern form, and information was lost in the transition.
And really, 900 years is a long time. Information has a way of degrading, even in computers. The very atoms of the storage medium can undergo spontaneous quantum state changes or be damaged by cosmic rays, introducing errors and corruptions into the data. The older the memory, the more it deteriorates. The Borg don't have historians, don't consult their knowledge base unless they have an immediate need for it, so a lot of old data would just sit on a virtual shelf slowly falling apart. Maybe 900 years is a little quick for that deterioration to happen, but the Borg aren't innovators, so they don't necessarily have the ability to improve on what they have.