Is it? I don't know what other device she could use that would draw people in as easily. Remember that before it became the story we talk about, it had to be the story we read. And it's not a story you want to read. If you told it with characters more clearly drawn, it would be about their reaction to the central premise. If you told it less poetically, it wouldn't have the mythic magical realism that keeps you from thinking about the logic, instead of the question.

I thought it was ridiculously ham-handed and obvious until I realized that a lot of people still didn't get it.

Some things that are fine in exceedingly short stories wouldn't work at all in a novel. Other SF authors have really short stories like that: Asimov, Wolfe, etc. When the story is less than four pages long one can afford to re-read the awkward parts.