|My best friend Justean hugging the "free hugs" zombie|
|The first zombie movie|
I think there could be a couple reasons. Scientific advances and the threat of another nuclear disaster may be one reason. If it is possible to extend lives or cause deformities in children thanks to radiation, is it possible for an accident to create zombies or zombie-like creatures? Perhaps People wanted to substitute sparkly vegetarian vampires for a tougher image like zombies. Yes, werewolves may also appear to be tougher, but the Twilight ones were just too polished and baby-faced. :P With zombies, there is no mercy. There is no empathy, only instinct.
Zombies are such adaptable beings. There are no set rules like with vampires (which is why the sparkly ones were a terrible idea). There can be Voodoo zombies, disease zombies, semi-intelligent ones, zombies who can use tools, and even lovable servant zombies (Fido).