Enough dialogue?

I understand that a movie can suffer when too much of its plot or the social implications are discussed by the actors and actresses in the film. However, while I did like this movie, I wonder if anyone else felt there was not enough discussion of what was going on and why? I think Nancy (Veronica Cartwright) did the most heavy lifting in terms of social commentary. Like when she stated, 'Of course, nobody would notice, our air is so polluted, we're overwrought with chemicals and toxins. Who would notice if a flower were poisoning us?' But otherwise, we get very little background. There's a little from Leonard Nimoy's character, but it amounts to a single line about solar winds blowing the spores from a dying planet.