I have a theory: I think Harry is going to be stripped of his magic.
If the final battle happens before the end of his 7th school year, and once again the AK curse that should end it all backfires some how, Harry is still left "alive" but without his magical powers. He has survived *to* his 7th year, but if his magic is stripped he will not be able to last *through* his 7th year. (School year. Yeah, it's a long shot.)
Now, regarding the whole death thing. Voldemort obviously took measures that we are unaware of, but he did that himself. Harry can't have done anything similar, but Dumbledore and every body else could have. Besides Lily's sacrifice protection, we know Dumbledore's had a hand in protecting Harry by placing him with the Dursley's, and even his insistence that Harry learn Occlumency.
So why didn't Voldemort die? Well, we don't know specifics, but we know that he was attempting to conquer death and partially succeeded.
Why didn't Dumbledore try to kill Voldemort in the Ministry? Because Harry has to, since Voldemort's marked him and fulfilled that part of the prophesy.
How do we know that Voldemort will definitely die? Because Harry
has the ability to love, giving him the advantage over Voldie. Somehow. (Told you, long shot.)
How do we know they won't BOTH die? That was given to us the the prophesy. "Either must die at the hand of the other for neither can live while the other survives." (My good friend Merriam-Webster defines "either" as "the one or the other.")
So, maybe JKR is being playing the devil's advocate by suggesting Harry won't make it through the series. Another famous red herring. Maybe he won't, and then after the shock of the end of book seven you can dance around and sing "ha ha I told you so!" and we will all bow to your superior insight. Or maybe he won't make it through in the most technical sense.
Or maybe I'm just on crack?
So..... that's my theory!
ETA: I posted this as a comment on
Cybele_san's journal and reposted it here.