But then again, since the attack on Earth apparently never happened in the original timelime, the Borg probably shouldn't have existed in the first place .......
It may be that the Borg are simply an evolutionary endpoint and that, if that evolutionary niche isn't filled, then someone else will evolve to fill it. It's possible that, in the post-Enterprise
iteration of the timeline this is
the origin of the Borg, while in past and future iterations the Borg origin is different. Or, to borrow an Asimovian concept, there's a "line of maximum probability," and certain events are fated to happen, barring massive changes to the timeline.
There's also the possibility that the degredation of the Caeliar of Mantilis is a red herring. In this view, the Borg predated 4500 BCE (Probe
, and New Worlds, New Civilizations
all make references to Borg incidents hundreds of thousands, even millions, of years in the past, for example). The encounter between the degraded Caeliar, which had already taken on Borg-like qualities, and the Borg-proper may have made the Borg far more dangerous than they had been previously.
On the third hand, there's also the existence of the Borg in the Mirror Universe, per Greg Cox's novel, to consider. Would the Borg share the same origin in the Mirror Universe that they do in the "normal" universe? Would the Caeliar allow the morally-suspect crew of the Mirror Columbia
to even get close to Erigol? As the Borg exist in the Mirror Universe, their origins may differ.
Do I think any of these are right? Not really; I just like spitballing ideas.