Perhaps they received negative feedback from the fanfiction community. If they constantly got criticized for their writing style, plot choices, or character interpretations, it could discourage them to the point of quitting. Also, real - life commitments such as work, study or family might have taken over, leaving no time for writing fanfiction about Naruto.
It might be due to a lack of inspiration. Writing fanfiction requires continuous creativity, and if they ran out of new ideas related to Naruto and the ninja world, they could decide to quit. For example, they might have explored all the character arcs and plotlines they could think of within that context.
It could also be due to personal growth. Naruto might have outgrown the ideals and limitations of being a Konoha ninja. He may have developed his own set of values that no longer align with the village's ninja system. For example, he could have found that the constant focus on missions and loyalty to the village overshadowed the importance of individual freedom and justice on a broader scale.
Perhaps Naruto quits Team 7 in the fanfiction because of a betrayal. He might find out that one of his teammates has been secretly working against him or has lied to him about something really important. This could shatter his trust in the team and make him want to leave. Or it could be due to an accumulation of small incidents. Like constantly being the one to get in trouble for the team's mistakes, or not having his opinions heard when it comes to team strategies. Over time, these little things can build up and make him feel that he's better off on his own.
One possible reason could be that Naruto realizes the Chunin Exams have become too dangerous and he doesn't want to risk his life or the lives of his friends. Maybe he sees the dark side of the competition, like how some contestants are willing to cheat or harm others to win.
One reason could be a sense of not being understood. Maybe Naruto feels like his teammates, Sasuke and Sakura, don't truly get him. Sasuke is often preoccupied with his own revenge, and Sakura has her eyes mainly on Sasuke. Naruto might feel left out and that his goals are not aligned with the team's, so he decides to quit.
Perhaps an injury could cause him to quit. If he gets seriously hurt in one of the early rounds and realizes that continuing could lead to permanent damage or even death, Naruto might choose to step down. He's brave, but not foolish. He also has dreams of becoming Hokage and if he thinks that by continuing in the Chunin Exams in an injured state he could jeopardize his long - term goal, he would rather quit and live to fight another day.
It could also be due to a major disagreement with Kakashi. Maybe Naruto has a different vision for how they should operate as a team or a particular mission that goes against his values, causing him to leave.
It might inspire other writers in the community. Some might see it as an opportunity to fill the gap and start creating their own unique takes on Naruto - related stories. For example, new writers could emerge trying to recreate the kind of stories the 'quitting' writer used to write.
One possible reason could be that he gets tired of the constant fighting and bloodshed. He might have seen too many friends get hurt or die, and it just becomes too much for him to bear. Another reason could be that he discovers a new purpose in life outside of being a ninja, like focusing on family or helping the village in a non - combat way.
One possible reason could be a lack of inspiration. Creating fanfic requires continuous creativity, and if Boruto has run out of new ideas, he might quit. Another reason could be time constraints. Maybe he has other important commitments in his life, like school or work, that leave him with no time for fanfic writing. Also, it could be due to negative feedback. If he received a lot of criticism on his fanfics, it might have discouraged him from continuing.
Maybe he feels betrayed. In fanfiction, there could be a situation where his fellow Justice League members keep secrets from him. For instance, Superman could be hiding something about his true powers or his origin that could potentially be dangerous. Batman, being the detective he is, values truth and transparency, and such secrets might make him feel that he can no longer trust his teammates and thus quit.