If that is the case and Borg want to assimilate Earth 24th century technology so bad. Why sent one cube
. Heck wouldnt it be better sent 2 or 3 cubes to assimilate Earth or just hold one cube at Federation border and if the Cubes fails their mission.
The single cube here and in BOBW seem at odds with Guinan's statement in Q Who:
RIKER: Guinan, if they were that aggressive, why didn't the Borg attack? They could have but they didn't.
GUINAN: They don't do that individually. It's not their way. When they decide to come, they're going to come in force. They don't do anything piecemeal.
Speculative wank: the bulk of the Borg fleet is in the Delta Quadrant and it would take many years for them to get to Earth. They don't have a lot of cubes available for Alpha Quadrant operations, and that's why they use only one when they expect one to be sufficient.
The idea that it would take years for Borg to get from Delta to Alpha would seem to be contradicted by VOY:Endgame, but at the time that BOBW and FC were made, Endgame hadn't even been conceived.
I find it interesting that Janeway's Endgame tactic is the same one used by the Borg in FC: traveling back in time with modern military technology to attack a relatively primitive enemy before they developed the means to defend themselves against it.