In my opinion Akira got nothing "wrong", because it is clearly more a supernatural dystopia than a science-fiction world.
First, the manga and the anime were both based on the immediate destruction of Tokyo — 1982 for the manga, 1988 for the anime. A new megalopolis called Neo-Tokyo is built over, and the story starts, in 2019.
Then the main theme, the psychic powers induced by drugs, are more akin to the genres of horror, fantastic and superheroes than to the science-fiction genre.
