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.
In the fanfic, it could be that Naruto has faced too many disappointments regarding Sakura. For instance, Sakura may have repeatedly chosen Sasuke over Naruto in crucial situations. This continuous rejection could lead Naruto to stop caring about her. Moreover, as Naruto matures, he might understand that his feelings for Sakura were more of a childhood infatuation, and now he has a different perspective on relationships and priorities.
Maybe in the fanfic, Naruto discovers that Sakura has some traits that he doesn't admire as much as he used to. For example, her sometimes over - emotional and jealous behavior towards Sasuke. This could make Naruto gradually lose interest in her. Also, Naruto might meet other people who have a more positive impact on his life and values, which shifts his focus away from Sakura.
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.
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.
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.
It could be that Naruto has outgrown his initial feelings. As he matures, he starts to view Sakura more as a friend. In the fanfic, his experiences in the ninja world might have changed his perspective on love. He might have seen so much pain and sacrifice that he no longer wants to hold on to a love that might be one - sided or not as fulfilling as he once thought. Also, Sakura's continued love for Sasuke in the fanfic could be a factor that makes Naruto step back.
Perhaps the story then delves into Naruto exploring new love interests. He may meet a girl who shares his values and dreams more closely. Meanwhile, Sakura might start to realize what she has lost in Naruto. This could lead to some tension or even a new dynamic between them where Sakura tries to win back Naruto's attention but he is no longer interested.
One possible reason could be that the author wants to focus on other characters. Maybe they feel that Naruto's story has been told enough in the fanfic and it's time to give other characters the spotlight.
One possible reason could be that he has been through so much in his original adventures that he's just tired. He might feel like he's constantly being put in new, often contrived, situations in the fanfiction and he simply wants to step away from all the chaos and drama.
One possible reason could be that Naruto's character development leads him to focus more on other aspects like his ninja duties or his bond with other friends. As he grows, his priorities shift.
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.
She might be too busy with her own life in the Naruto universe. There are so many things like battles, relationships, and her own growth that she has to deal with. Fanfiction is just not on her radar.