One possible reason could be that he was severely injured in a battle. Maybe he got his legs broken or had some internal damage that affected his ability to move them. For example, if he fought against a really powerful enemy who used a jutsu specifically targeting his legs, it could leave him unable to walk.
It also gives a chance for new characters to be introduced. Maybe a healer or a mysterious figure appears to try and help Naruto regain his ability to walk. This can introduce new plot twists and expand the Naruto universe in the fanfiction.
One possible reason could be that he was injured during a battle with dark wizards. Maybe he was hit by a powerful curse that affected his legs. Another reason might be related to some kind of potion gone wrong. For example, if he accidentally drank a potion that had negative side effects on his motor functions.
Maybe he got injured during a dangerous adventure. For example, he could have fallen from a great height while chasing a dark wizard and broken his legs.
There may be many reasons for the inability to lift the left leg when walking, including poor posture, local cold, excessive exercise, lumbar disc protrusion, arthrosis, common peroneal nerve injury, lumbar vertebrae disease, Alzheimer's disease, cervical vertebra disease, cerebral vasculopathy, etc. These symptoms could lead to muscle weakness, nerve compression, poor blood circulation, and other problems, which in turn affected the ability of the left leg to move. It is recommended to seek medical attention in time for relevant examinations and diagnosis to determine the specific cause and carry out corresponding treatment. In addition, keeping warm, resting properly, and avoiding excessive exercise were also ways to alleviate the symptoms.
Maybe it's because a lot of Naruto fanfiction has become very clichéd. There are always the same overused plotlines, like the main character being an overpowered self - insert. People get tired of reading the same thing over and over again.
In the 'Harry Potter can't walk fanfiction' when Harry loses his ability to walk, the story could develop in a very emotional way. His friends and allies would be determined to find a way to restore his ability to walk. Meanwhile, Harry himself might start to see the wizarding world from a different perspective. He may notice things that he overlooked before when he was able - bodied. He could also become a symbol of perseverance for other students who are facing difficulties. The story could also involve Harry learning to use magic in new ways to compensate for his lack of mobility, such as using telekinesis spells more effectively.
In 'You Can't Just Walk on By', the title itself gives a sense of urgency and responsibility. It could be that the protagonist is faced with a difficult choice or a moral dilemma. Maybe they encounter someone in need, like a homeless person on the street, and the story explores how they deal with that situation instead of just walking away as many people might be tempted to do.
Well, in some fanfiction, the story might be set in an alternate universe where the whole ninja concept doesn't exist. So, Naruto can't be a ninja because there are no ninjas in that world. It could be a world with different power systems, like magic or super technology.
Well, in the Naruto universe, there's no concept of fanfiction. Naruto is busy with his ninja world stuff like fighting bad guys, training, and protecting his village. Fanfiction is something created by fans in our real world, not part of his world. So, he simply can't access it because it doesn't exist in his realm.