Well, come on! I think that the authors weren't thinking of Merriam-Webster when using the term "immortal" but Vampi is more immune to death than a human.
Now, as to your first question, it depends what movie you're watching or what book you're reading. For this example let's say that we're talking about the vampires from Anne Rice's series (beginning with Interview With A Vampire, which I have read half of). In the case of Rice's vampires, they need blood for some of the same reasons we do--to move and to keep our organs running. With these vamps, their only weaknesses are lack of blood, continuing to eat someone once they've died, and the sun (well, that's it as far as I've read).
These weaknesses were only created to keep the readers on their toes, not sure whether or not the vampire lives. Saying that they are indefinitely immortal ruins the ending! Like...in that lame ABC movie...the one with Ashley Tisdale, and some school dance...one of the actors was Max from Life With Derek... Anyway, in the commercial, they showed Max asking Ashley, "Will you go out with me?" which gives away what the entire movie was building up to! It makes watching the movie completely pointless, just like watching The Sixth Sense after I told you that Bruce Willis ends up being the ghost. (Apparently no one knows that. Go figure.) Would you read a book with this made-up synopsis?:
Chris just lost his mother when she mysteriously died in her sleep...or did she? Chris noticed two little marks on his mom's neck, an open window in her room, a strange man at the funeral and absolutely no other clues. He knows this much, and that the man is a vampire who has super strength, super senses, and, oh yeah, cannot be killed no matter what. In fact, Chris has no chance of beating the vampire. This, however, does not stop him from pursuing the vampire. Chris can't win this fight. Or can he?
Just kidding! He can't!That's on my wish list!
Yes, authors should tone down the use of the word "immortal" but how else will they get us to read? And anyway, vampires are so extraordinary that these few weaknesses are like minuscule cracks in a large, thick, sturdy wall. It doesn't matter very much and won't make much of a difference unless they chisel in the right spot.
Answering the second question, I have a question in return: Do you mean hunters that are vampires or hunters that hunt vampires? If the latter, then I have to say otherwise.
Who wants to hear a story about how the bad guys won? Unless you're reading from the perspective of the bad guys, in which case they would usually be the good guys. I'm sure that if vampires existed there would be millions upon millions of stories where the vampire hunter was killed, captured, turned, or eaten. But even then, the only stories that we would ever hear of would be those that told of how the hunter destroyed Vampi.
It's not that the hunter always wins--it's that those winners are better publicized.
That's all I have to say.
Your BEDA Blogger,
P.S. Dahlia, you did ask us to challenge your theory.