38 Years Later, Calvin and Hobbes' Lost Character Remains Bill Watterson's Biggest Failure

The author Lois McMaster Bujold has said that “the writer should always reserve the right to come up with a better idea.” That's a useful guideline for any reader to keep in mind. As any long-form story evolves, it usually picks up a few dead plot branches or abandoned characters, because the author can exercise their option to drop what they're doing for any (or no) reason. Sometimes it's not a continuity error; it's a deliberate change in direction.