It's not a question of sending a "message". It's how you want the readers to feel, having read the story.
A. Do you want them to think "Ok, everyone's dead, time to move on to the next thing".
B. Or do you want them to think "This story reveals something I didn't know before".
C. Or "I spent a lot of time reading this story, I wasted it".
D. Or "This story really made me think how I would act in the same situation".
E. Something else
Because how you end the story makes a big difference. Is there an emotional payoff? Or is the reader going to feel cheated? If the journey doesn't justify the end, they're going to feel that. And this gets built throughout the story. If you're building something that screams "The heroes are gonna find a way to save the world!", and then it doesn't, many people will feel cheated.
Unless you're subverting that ending, but subverting doesn't mean the obvious ending doesn't happen. It can mean, the obvious end DOES happen, but... Or it can mean it was obvious all along, but they didn't accept it, but I'd hate that unless I really disliked the characters. And a myriad of other options.
A. Do you want them to think "Ok, everyone's dead, time to move on to the next thing".
B. Or do you want them to think "This story reveals something I didn't know before".
C. Or "I spent a lot of time reading this story, I wasted it".
D. Or "This story really made me think how I would act in the same situation".
E. Something else
Because how you end the story makes a big difference. Is there an emotional payoff? Or is the reader going to feel cheated? If the journey doesn't justify the end, they're going to feel that. And this gets built throughout the story. If you're building something that screams "The heroes are gonna find a way to save the world!", and then it doesn't, many people will feel cheated.
Unless you're subverting that ending, but subverting doesn't mean the obvious ending doesn't happen. It can mean, the obvious end DOES happen, but... Or it can mean it was obvious all along, but they didn't accept it, but I'd hate that unless I really disliked the characters. And a myriad of other options.