Why haven't the Borg tried to assimilate the Talosians from Talos IV?

Question

As this answer eloquently states, the Talosians have a lot to offer, both in terms of their leftover tech from before they were driven underground and in terms of their ability to project illusions light-years away. Assimilated Talosians would make Borg expansion that much easier.

Borg have also assimilated Federation officers. They've taken many ships. Surely they must know that this planet exists. Why not give it a go? The Borg would surely have greater strength to resist the Talosians' mental efforts; they have trillions of minds to work with.

Answer 1

1. There's no guarantee they know it exists

2. The Talosians are really really good at hiding. In the video in the spoiler below you'll note the shuttlecraft itself is freaking out, believing itself about to be sucked into a black hole.

   NOTE: minor spoilers in the video from Star Trek: Discovery Season 2 if you've not seen it

If the Talosians can cause a shuttlecraft to think better of going there, I have no reason to believe a Borg vessel would not think the same.

Answer 2

The problem with the Talosians is that they've demonstrated the ability to fool minds so easily and thoroughly that it would be trivial for them to cause anyone they wanted to do things like blow up their own ships, thinking they were doing something else entirely. The only reason they don't is because they're generally not malevolent, and they're interested in what other species would come up with in their own minds.

The Borg don't have anything to offer, so the Talosians have no reason not to get deadly right from the start, and the only way for the Borg to protect themselves is doing what others have done, namely obliterating the Talosians. Further, the Borg, based on the examples of Hugh, Unimatrix Zero, and what (apparently) happened to the cube in Star Trek: Picard, respond to attempt to manipulate, infiltrate, or subvert by immediately cauterizing the wound. It's likely the Borg would detect that something was manipulating the minds of drones on a vessel approaching Talos IV, and the immediate, automatic reaction would be to cut the connection to the rest of Collective. The Talosians would be a particular threat because the Borg would be basing their information on data they're receiving from their drones, and if the drones are being subverted, there'd be a real threat they could put the entire Collective at risk due to bad data. We've seen that the Borg's internal network security is, quite honestly, crap, as they've been hacked multiple times, so that would be a concern for them.

Answer 3

Going by Star Fleet's information, the Borg would assume Talos IV was an uninhabited planet with some sort of lethal space plague. There would be no reason to look at it, and every reason to avoid it.

General Order 7 doesn't reveal anything about what was there. It seems unlikely to be people. If they were primitive but exploitable, the Prime Directive already protects them. If they were dangerous, how? They don't have space flight. But for any sort of race, Star Fleet would engage with them in some way. Anthropologists, negotiators ... something. If they were a dying race of super-telepaths which could only be saved by human volunteers, Star Fleet would have kept trying to help them. A ban would have been ridiculous in that case.

The order is basically a quarantine. The planet has something the Federation is terrified of, which is contagious (otherwise people could just go there and die. No harm done to anyone else, no need for the rule). It might not be a threat to the Borg, but could be, and the Borg aren't all that interested in research anyway. The Omega Particle is an exception, but Star Fleet handles those incidents differently.

Whatever Talos IV has, the humans did the hard work learning to avoid it, with the Borg as beneficiaries of that knowledge. Assimilation works.