The Borg are networked by nature. Hurting one part of the net may not mean much. But hurting the whole net may mean everything, even if it only physically manifests as damage to the one part the limited, non-networked camera is watching.
Which is the cool thing about the Borg. We never know, because the vast bulk of their iceberg remains hidden from view.
The Borg being ancient is unlikely to be a lie, even if we can't completely disregard that possibility. Attacks against their network should be something they are quite thoroughly adapted to, then. And since they are in the questionable habit of letting the first blow connect, one of their adaptation processes no doubt is "rebuilding everything after catastrophic failure"... So PIC could have its fairy cake and eat it, too, because the Collective could be down for good between the 2370s and the 2410s, say, and yet back up from May 21st, 2411 on. Or then from May 22nd, 2400 on...
Timo Saloniemi