Hollywood's Obsession

Hollywood seems obsessed-- for now-- with stories set in post-apocalyptic Earths where humanity is struggling to survive.  The cause of the disaster is often an alien invasion.

Of course, aliens bent on making Earth their own would have no need to mount a military-style invasion.  Redirecting an asteroid or two to collide with Earth would end all human resistance before it began.  Or, if They wanted the place intact, introducing a virus that would wipe out humanity would be relatively simple.  Those storylines, however, leave little room for Tom Cruise to play hero.