One possible reason could be that Naruto has faced so many betrayals and hardships in the fanfiction. For example, if his friends turned on him for some contrived reasons, it might lead him to stop caring. Another reason could be the constant failure in achieving his goals, like protecting the village but always being undermined by political intrigue within the fan - made story.
One possible reason could be that Naruto has faced too many betrayals. Maybe his friends turned on him in the fanfic, which made him lose faith and stop caring.
I'm not sure specifically as there could be many different takes on it. It might be a fanfiction where the character Izuku reaches a point of apathy or stops caring about things he previously held dear, like his dreams of becoming a hero or his relationships. It could be due to some traumatic event or a slow build - up of disappointments in the story's universe.
His character development takes a negative turn. Instead of being the optimistic and determined Naruto we know, he becomes apathetic. His once - strong sense of justice fades away.
One possible reason could be that Naruto has finally realized that Sakura's heart has always been with Sasuke. After years of chasing after her and getting constantly rejected or overlooked, he just gets tired and decides to move on. He might start to focus more on his own personal growth and the other relationships in his life that are more reciprocal.
Well, perhaps it could be that Stiles has faced so many difficult situations in the original story that he just reaches a breaking point and decides to stop caring about the things that used to bother him. Maybe he stops caring about the supernatural threats in his town, and this could lead to a series of events where his friends have to try and bring back the old Stiles.
One possible reason could be that Naruto realizes Sakura's unrequited love for Sasuke. He might feel tired of always being in a one - sided emotional situation with her. Another reason could be that Naruto has his own goals and growth to focus on. His journey to become Hokage and protect the village requires all his attention, leaving little room for his previous feelings for Sakura.
It could be a new character introduced in the fanfiction. Maybe a powerful witch who has the ability to manipulate emotions. She targets Stiles and makes him stop caring as part of her evil plan to disrupt the balance in the town. Since Stiles is an important part of the group, his change in attitude would cause chaos.
Well, it makes the triangle less of a love triangle. With Naruto out of the picture in terms of caring for Sakura, it becomes more about Sakura and Sasuke's relationship without Naruto's interference. Sasuke may not have to deal with Naruto's rivalry in terms of Sakura's affection anymore.