... (We house ruled that the homeworld always generates 1 production with a node, even if you don’t have any ships in orbit).
Pretty sure this is not per the rules or FAQ but nothing wrong with house-ruling it.
My one experience with the Borg was similar, we were so distracted that no one made much effort to actually confront the winning player. The thing about the Borg is that with proper delaying tactics they are actually somewhat of a slow building threat, especially if they don't come out early game. It's impressive how fast players can rocket to cultural victory even with Cubes on the board.