How did Star Trek become so believable?

Answer 1

Creator Gene Rodenberry was, for a time, a hardened cop; however, an experience late in his career as a cop, when he was poised to retire, made him change his mind about the human race. I think Rodenberry saw a hardened, vicious criminal, change dramatically from cold blooded killer, to a sincerely kind hearted and productive human being. I'm not sure of the specifics but the experience inspired him to make Star Trek; his thinking was that if a seemingly hopeless criminal has hope of changing, then the human race does too.