Species with a Collective Consciousness Leads to Extinction?
The film never explains why this is the case. I could possibly understand a species that is already accustomed to individuality and then being destroyed by a shift to a collective consciousness because it becomes unbearable, but like Emma says in the film, if that's all the species knows then you would think the reverse might lead to the destruction of that particular species. Not the continuation.
And who's to say either of those scenarios would lead to extinction? In each circumstance the species could adapt. I know this is all speculative fiction but in Star Trek the Borg seem to do alright.