There is no end.
The coma-dream thing has been brought up before and vehemently denied by Kirkman. Everything is real. There's not going to be any reset button.
The only cure we'll get is a spike to the head. All references to the cause have been very vague and ambiguous. According to Kirkman, the cause and the cure are irrelevant to any story he wants to tell. He's only concerned with how people are dealing with the situation at hand.
Kirkman's own words: "Whatever makes people come back as zombies after they die--it's inside them. It's inside everyone. No matter how anybody dies, as long as the brain is intact... they turn into a zombie. Well... bites, and direct to blood contact with zombie gunk, [...] causes death. It's a strong infection that leads to fever that kills someone. Then the 'virus' or whatever is already in them... turns them into a zombie."
It seems to act like a virus, but there's no evidence. Even that episode at the CDC, Jenner said it could just as easily be supernatural.
Jenner: It invades the brain like meningitis. The adrenal glands hemorrhage, the brain goes into shutdown, then the major organs. Then death.
Jenner: It could be microbial, viral, parasitic, - fungal.
Rick: Or the wrath of God?
Jenner: There is that.
Kirkman even considers this episode a mistake, because he doesn't want any significant information about what's creating zombies.
How about this twist: all the living people are part of some mass delusion that makes them see dead people, and they're just killing normal people they think are zombies. Yup, little Coral, you killed your very healthy mom.
They are the real zombies, and what they view as being infeted are the real people!