What could be the reasons for 'Harry and Hermione quit fanfiction'?

It could be that he has a bad accident in the potions lab. For example, a potion explodes and nearly kills him or one of his friends. This traumatic experience makes him lose his confidence and interest in potions, leading him to quit as seen in some fanfictions.

Another reason could be negative feedback. If they received a lot of criticism from the readers, such as complaints about the plot not being true to the original spirit of Harry Potter or the characterizations being off. This continuous negative response might have made them lose their enthusiasm and finally quit caring about writing the fanfiction.

One reason could be to escape the trauma of the war. They've been through so much in England, and leaving gives them a chance to heal in a new environment.

One reason could be to search for a powerful magical artifact outside of Hogwarts that they believe is crucial for defeating a new dark threat. In fanfiction, they might feel that Hogwarts has become too dangerous or restricted in terms of resources for their mission.

One possible reason could be their different career paths. Harry might be more focused on Auror work which is dangerous, and Hermione, being the practical person she is, may not want to live in constant fear for his safety. Another reason could be a growing apart in their values. Maybe as they get older, Hermione realizes that Harry has a more impulsive nature when it comes to making decisions regarding the wizarding world's politics, while she prefers a more calculated approach.

One reason could be the media attention. After all they've been through, they might be tired of constantly being in the spotlight. The British wizarding press could be hounding them, so they leave to get some privacy.

One reason could be to start anew. After all the turmoil in the British wizarding world, they might want a fresh start away from the memories. The USA offers a different magical landscape with new opportunities.

Maybe it's about her study habits. For example, she always preaches about everyone following the rules in class and doing their homework properly. But then she might break a minor rule herself when it comes to getting access to a certain book in the library for her research.

Perhaps there is some external threat or danger related to Quidditch. Maybe there is a dark wizard who is targeting Quidditch players and Harry doesn't want to put himself or his friends in danger. He has already faced so many threats in his life that this additional risk related to Quidditch might be too much for him.

One possible reason could be a sense of being too powerful and outgrowing the team. If Naruto in the fanfiction has become 'godlike', he might feel that the training and missions of Team 7 are no longer challenging enough for him. He may seek greater challenges elsewhere.