I read a book on this. As time goes by the audience will tend to accept certain ideas and ignore others. Voodoo is just seen nowadays as misguided belief. The Zombie movie appeals more to science fiction fans in general than horror fans. Viruses are real and they are scary. Alot of people are germaphobic. This doesn't mean Voodoo zombie films don't appear out of nowhere. Also, most Zombie movies are based after Romero's conception. Post NOTLD zombies had no solid definition, zombies could be anything. There are surfing zombies in I was a Teenage Zombie. After Romero it became pretty clear to be a zombie a creature has to fall into this definition
Romero Zombie:
Dead, Lumbering, Mindless, Cannibalistic, Viral
Russo Zombie
Dead, Lumbering, stupid and hungry, Cannibalistic, Viral
Snyder Zombie
Dead, Kenyan Fast, Mindless, Cannibalistic, Viral
Boyle Zombie
Living but infected, quick or slow, Mindless, murderously violent, Viral
Mikami Zombie
Dead and mutating, Lumbering, Mindless, Cannibalistic, Viral
Classic pre-romero Zombie
Totally Random, depends on individual movie
Voodoo
A mindless SLAVE, who has arisen from the grave, in reality is poisoned by a chemical which creates undead-like
symptoms. Partly related to the Vampire mythos, partly real. Giving someone Tetrodotoxin and giving them a
dissociative drug.
Revanents
Dead, Lumbering, Cannibalistic, to some extent Viral