system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Trek: First Contact] If the Borg can travel through time then why haven't they assimilated everything?
gpt
The borg aren't interested in assimilated primitive civilisations. The entire point of assimilation is to take incorporate new biology and technologies into the borg collective, so they can continue to advance. The borg don't bother with civilisations they consider primitive or worthless, such as the Kazon. Going back in time to assimilate the galaxy basically defeats the entire point of assimilation. They only attempted it with the Federation because they'd become too much of a threat compared to their relatively low tech in comparison with the borg.