I ventured back the Reading Room for a bit tonight. (Hope that wasn't a mistake; I can easily lose a lot of time reading posts there.) And one post struck me. I've discussed various things with Beren IV previously, and while I think he's quite intelligent, he seems to fail to grasp some of the things I argue because he doesn't approach from the proper perspective.
Anyway, he wonders about the believability of a story that doesn't have more people die from objective hazards. That is to say, why do people in LOTR not die just from bad luck or the accumulation of chance? I didn't read all the replies, and because I didn't, I'm posting my thoughts here instead of there.
There is a very simple answer, which is that it is necessary for the plot that the heroes not die at the wrong times. Even in true stories, we don't read about the people that die at the beginning of what would be the tale. Because then there isn't any tale. No one wants to read a 20 page book about a hero who falls, unluckily, to a chance arrow just as he sets out. Even in real life we only read the stories of men who lived long enough to accomplish something.
So when we start a book, we begin with an expectation that the hero, or one of the heroes will survive throughout or at least until right to the very end of the book. So much suspension of disbelief is required to even get the story going.