One reason could be that Naruto doesn't feel like he fits in with the ninja culture. He might be more of an individualist and find the strict hierarchy and rules in the ninja world too confining. He could also have had some bad experiences during his early ninja training, like being bullied or feeling left out. Another possibility is that he has discovered other talents within himself that he wants to explore, such as cooking or music, and he feels that being a ninja would take away from his ability to pursue those interests.
It could be that Naruto has other creative or intellectual interests. For example, he might be more interested in art or learning about the history of the ninja villages rather than participating in ninja battles. He could find the rigid ninja training and the constant competition unappealing. Also, perhaps he has a different sense of purpose, like wanting to focus on building peace in a non - combat way, which doesn't require being a ninja in the traditional sense.
In some cases, the fanfiction might be a crossover with another universe where the idea of a ninja doesn't fit. So, to make Naruto fit into this new universe, the writer has to take away his ninja identity. This allows for new and interesting interactions between Naruto and characters from the other universe.
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.
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.
One possible reason could be that he experiences a great personal loss. Maybe he loses someone very dear to him during a mission, like his best friend or a respected mentor. This loss makes him question the whole ninja life and all the violence and danger it entails, leading him to give it up.
One possible reason could be that he experiences a great loss, like the death of a dear friend. This might shatter his confidence and make him lose his passion for being a ninja.
Well, Kushina could initially be disappointed. But then she might see it as an opportunity to help Naruto find his true passion. She could start introducing him to different things, like maybe some traditional Uzumaki family skills that don't necessarily involve being a ninja in the typical sense. This way, Naruto could still have a sense of purpose and connection to his heritage.
He may dislike it because he feels that it undermines the real struggles and achievements of the ninja. In fanfiction, things might be made too easy or unrealistic. He has fought tooth and nail for everything in his ninja life, and seeing it made into something that doesn't represent that in fanfiction would make him hate it.
One reason could be her strong connection to Naruto. Since he's her son in the Naruto universe, she might be interested in seeing different interpretations of his story. Fanfictions often explore new aspects of characters and their relationships, and she may enjoy seeing how others perceive Naruto's journey.
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.
One possible reason could be the fear of losing his loved ones. In the original Naruto story, many ninjas sacrifice a lot, including their lives. Naruto might have seen this and decided he doesn't want to put himself in such a position.