Vampire shows have been a steady fixture on TV for decades, going back through Buffy/Angel and Forever Knight at least.
Exactly. It's not like this is some pernicious new trend. It's just a tv staple, like space operas, spy shows, or courtroom dramas.
Zombies, on the other hand, have never
appeared regularly in prime-time before. The idea of a doing a weekly tv series about a zombie apocalypse is actually a pretty radical and original notion . . .