Re: Has B&B ever indicated why the Borg failed to assimilate the Feder
^Are you guys referring to the transwarp conduit in "Endgame?" That's not exactly a wormhole.
Anyway, the Borg have always had the ability to assimilate the Federation easily -- if they'd made the effort. We saw that one cube was able to do enormous damage, but we also saw that they had thousands of cubes back in the Delta Quadrant, and the ability to cross the galaxy pretty easily at transwarp. But the thing people tend to forget is that from the Borg's perspective, the Federation was a minor, distant entity, actually pretty low on their list of priorities. That's why they only sent one cube at a time on an occasional basis. They had bigger concerns closer at hand, like dealing with all the local powers fighting against them in the Delta Quadrant, and later dealing with the war against Species 8472. The Federation was clear on the other side of the galaxy, and while the Borg felt its biological and technological distinctiveness could be useful, it was far from their only target.
The Destiny trilogy in the novels shows what happened when the Borg actually did make the Federation a priority. As a result of Voyager's destruction of their transwarp hub and their Unicomplex in "Endgame," the Borg finally designated the Federation as a major threat rather than a potentially useful resource, and invaded en masse with thousands of cubes. It was the most destructive event in Federation history, and the Federation would never have survived unless... well, read the books.