"Of course we can use our imagination. I could've used my own imagination and imagined a much better story than this crap and not wasted my time watching it. If I were to imagine what caused the apocalypse of this movie, I could think of hundreds, likewise I could think of hundreds of possibilities of what happened after the end of the movie. The family could have truly been nice, took the kid in and they could've survived long enough for his kids to see a rebirth, or his dad might have been paranoid for a good reason, they might have taken him behind the next bush and slaughtered him. Such a wide range of possibilities is not for the purpose of "leaving it to your imagination" it is simply lazy writing. A well written story might not spell everything out for the viewer, but it doesn't leave holes this big either. A well crafted story would give clues and leave the viewer to come up with a list of finite possible conclusions, not an infinite scope of which the viewer might as well have crafted their own story from rather than trying to add this pointless piece into it. There is no point to trying to combine the viewers visions and the authors vision when it is this wide open. Doing so would be guaranteed to be apocryphal anyway."