End of the world movies have been common since the 50s.
Zombie movies are a phenomenon because it is a fairly good premise that can be recycled in different ways to tell different stories, and it almost always includes characters making stupid mistakes and getting themselves killed. This puts the audience in a unique position in movies, one where they like the movie just enough, but are frustrated at how stupid the characters are that it spawns a lot of discussions over beer about why they are so stupid, and why you would do things so much better.
brrraaaaaiiiiinnnssss!