For the ending of a story to work, there needs to be some kind of resolution. For a story to have resolution, there needs to be something to resolve, which means there needed to be something at stake. And the issue with Haley's Story was there was never anything meaningfully at stake except "who ends up together in the end", something that we each decided as players many, many episodes ago.
None of the subplots introduced after that ever threatened to change the arc of the story. So in a way at that point it was already over, and the whole remainder was essentially a Return of the King-sized epilogue.
Which is kind of when I checked out. "Great, the characters I want to be together are together, in the absence of a subplot that meaningfully changes that, I guess I'll just be watching them find different ways to shag over several updates until the developer wraps the story up."
Which they did, until they did.