No. I'm completely sure that zombies, along with vampires and all other fictional creatures of the dark are not real and will therefore never take over anything. I mean, the absurdity that the "great undead" could actually take over the world one person at at time is extreme. I think that's why we like them so much, because they are totally unreal and detached from day to day life.
Heh. No, but I find stories about zombies entertaining. It's kind of a safe way of dealing with fears about the actual scary things that could happen to our world (climate change etc.), as well a form of escapism.