In fact, I think this may be the fundamental difference between English Majors and the rest of the population . . . or at least one of the fundamental differences. Knowing the ending doesn't spoil the story for us. In fact, it enhances it. Doesn't Scrooge seem especially beastly because we know he'll get his come-uppance soon? And isn't his transformation all the more satisfying when we know and appreciate the arc of the story?
There's some value to following along, not knowing the outcome. That lets us join the characters on the journey. But real life is journey enough, with the outcome unknown. Literature gives us that second chance to appreciate the journey in context. Why else would a second reading (or in this case, many readings) be so enjoyable?
" . . . and it was always said of him, that he knew how to keep Christmas well, if any man alive possessed that knowledge. May that be truly said of us, and all of us!"