Elias Vaughn wrote:
I haven't seen Endgame in, like, forever, so someone correct me if I'm wrong, but... Didn't Janeway originally want to leave the hub alone until she was handed defensive technology that let Voyager handle Borg attacks, and a torpedo that could kill a Cube in one shot? Why would she ever consider the Federation to be vulnerable to the Borg if she had those?
The Borg inevitably adapt to any new defense in time; in fact, they adapted to the ablative armor in "Endgame" itself. The value of the new weapons was simply that they were new, that the Borg hadn't dealt with them yet and thus hadn't adapted. That made their benefit short-term at best. That's why Nechayev was so reluctant to authorize the use of transphasic torpedoes during the Invasion -- because the more they were used, the quicker the Borg would adapt to them and render them useless (like the way germs develop resistance to antibiotics and disinfectants if you overuse them).