Different comic books, or movie adaptations of comic books, involving the same character (perhaps slightly different versions of them) tend to have similar origin stories.
For example, in most (all?) versions of Spider-Man, Peter Parker gains his powers when he is bitten by a radioactive spider, and then witnesses his Uncle Ben dying, leading him to learn about his responsibility in protecting and helping others.
However, the manner of the bite (for example a spider that is in a museum or a laboratory) and the manner of his Uncle's death tend to vary slightly.
However, in every version of Batman that I am aware of, the origin of Batman stems from Bruce Wayne watching his parents be murdered by a mugger or hitman at night after going to the theater.
This seems really specific. Whilst the initial encounter that he has with with bats does actually differ through different iterations of the story, are there any Batman origins that don't involve him witnessing the death of his parents to a random mugging behind a theater?
If not, is there a reason why such a specific sequence of events always occurs?