About the ending of The Count of Monte Cristo
For Aristotle, in his Poetics, fiction is the art of lying well. The art of lying well consists of presenting something false and impossible, but combining it with something true, so that the audience, believing the second part, swallows the first.
For Aristotle, art works with the probable impossibility, which is an event that, in the real world (in physics, logic, and real-world history), is impossible to happen, but, within the internal logic of the story, seems perfectly natural, inevitable, and true.
The improbable possibility, on the other hand, is an event that, in the real world, is perfectly possible, but, within the plot, sounds forced, false, gratuitous, and breaks the causal logic of the story.
The spectator is not there to see a newspaper report or a documentary, which is what actually happened, but to see what should or could happen according to the logic of emotions and human characters. If a scene is emotionally true for that character, the audience accepts even the impossible.
Aristotle teaches that if something is impossible or irrational, the author could justify it if that makes the final effect more grandiose. Things are portrayed as they should be, which is idealization and people believe that it is true, even if it is not.
That is why we accept the way the count escaped, how he found the treasure, and how he infiltrated Villefort's house.
Within the very logic of the 2002 film, which follows the improbable possibility, we could accept that outcome. We could say that the ending follows the logic of idealization, of how the ending should be.
Manga, anime, and light novels that involve magic and harems may sound absurd by real-world logic, but within the context of the story, we accept them as perfectly plausible. Even the reincarnation of Ruby Hoshino and Aquamarine in Oshi no Ko might sound absurd by real-world logic, yet within the context of the story, the audience accepts it.
The book's ending is more realistic. The Count's ending with Haydée is much more realistic, due to the similarities they have with each other: betrayal, loss of freedom and of their fathers, and the pursuit of revenge. It strongly resembles Aleksandr Solzhenitsyn: when he was released from the Gulag, the reconciliation with his first wife, Natalia Reshetovskaya, did not work out very well. But he had changed too much, and they constantly fought. Later, he met the young Natalia Svetlova, who had a life similar to his; and despite the 21-year age difference, the similarities in their life histories brought them closer, and they stayed together. Like the Count and Haydée, their similarities united them.
But within the logic of the fiction itself, we could accept Edmond and Mercédès as viable.
But which ending would be more cathartic: Edmond returning to Mercédès, or Edmond leaving with Haydée?