I think Capote believed a story could be perfect, but my opinion is that it's the same as not being able to step into the same river twice. You're a different person each time you come to your story, and you're going to read it differently. In the preface to John Cheever's collection of stories he says that when he re-read his early works, he was embarrassed at how immature the writing was. But I'm sure at the time he thought they were the best things he'd ever done.