It could also be that he has other interests or dreams that he values more. Maybe he discovers a passion for something like scientific research related to quirks. He might think that he can contribute more to the world by exploring the origins and applications of quirks in a laboratory rather than fighting villains on the streets as a hero.
One reason could be fear. The life of a hero is full of danger. Izuku might have seen the toll it takes on heroes, like All Might's weakened state. He could be afraid of getting seriously injured or even dying. Another reason might be self - doubt. Despite his initial dreams, he may have come to believe that he doesn't have what it takes to be a great hero, in terms of both physical and mental strength.
Perhaps he realizes that the hero society has its flaws. He could have witnessed corruption or unfairness within it. For example, heroes might be more focused on fame and glory rather than actually helping people. Izuku, being a very empathetic person, might not want to be part of such a system. He might prefer to find other ways to make a positive impact on society that don't involve being a traditional hero.
The story could focus on Izuku becoming a hero - support figure. Instead of being on the front lines, he could use his intelligence to develop new technologies or strategies for heroes. This would be a different path from the traditional hero - becoming storyline.
One possible reason could be that he has seen the darker side of the ninja world. Maybe he witnessed too much death and destruction during his missions and decided he no longer wanted to be part of it. Another reason might be that he has other dreams that he realizes are more important to him than being a ninja. For example, he could have a passion for art or music that he wants to pursue instead.
One reason could be social pressure. In today's society, there is often an idealized body image that is thin. Girls may see these ideals in media, such as on social media platforms where thin models are highly promoted. Another reason might be related to self - esteem. She may believe that being thin is more attractive and thus doesn't want to gain weight to feel better about herself. Also, in some cases, it could be due to a fear of health problems associated with weight gain, like diabetes or heart diseases, even if the risk might be overestimated in her mind.
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.
Maybe he discovers other dreams or goals. He could find that there are other ways to protect the village and his friends that don't require him to be Hokage. He might be more interested in exploring the ninja world, learning new jutsus, or even teaching the younger generation about ninjutsu rather than taking on the political and leadership role of Hokage.
One possible reason could be stress. High stress levels from work, family issues, or other aspects of life can greatly reduce a person's libido. For example, if she has a very demanding job with long hours, she might be too exhausted at the end of the day to even think about sex.
One possible reason could be that Naruto has seen the dark side of the shinobi world. He might have witnessed too much death and destruction in battles, and this has made him disillusioned. For example, if he lost many friends in a major war, he could start to question the whole concept of being a shinobi.
One possible reason could be that in the fanfiction, his family might have decided to keep him away from the wizarding world for his safety. Maybe they feared the dark forces at Hogwarts, like Voldemort's followers.
One possible reason could be miscommunication. Maybe there were misunderstandings between Bingley and Jane that led to a breakdown in their relationship. For example, if Bingley misinterpreted Jane's shyness as disinterest.
One possible storyline could be that Izuku discovers a different quirk within himself. Maybe a latent quirk that was overshadowed by his admiration for All Might and One for All. For example, he could have a quirk related to intelligence amplification, which would make him a brilliant strategist in hero battles.