My weird take on fiction is that much of the appeal is that the entire story is just an elaborate analogy to explain true facts about human nature that are otherwise hard to make clear.

You could try to write a non-fiction essay about how being a parent sets you up for potentially the worst pain and most intense grief you can imagine but yet also the experience is so meaningful and rewarding that it's worth it. But that essay would be abstract and wouldn't really hit you in the gut.

Or you could read Ted Chiang's "Story of Your Life" or watch Arrival which is nominally completely made up about aliens that don't experience time like us and it will convey the same concepts more effectively than an essay could.

Totally, it's not a weird take though. It's actually a pretty standard fare account of the purpose of fiction in literary theory that's been with us for a long time.

There's actually deeper arguments to be made that storytelling was the first form of human abstraction (we only get the essential details pertinent to the story, all else is abstracted away) and much of what's core to all our practices of representation stems from an originary impetus for storytelling as a means of sharing and replicating knowledge. The prosaic, scientific, nonfictional, non hyperbolic writing we have all gotten used to is kind of a late development.

It doesn’t, really, which is okay, because the subtext here is that Pg is writing about essayistic writing, or more specifically, communicating ideas in the form of written words. I don’t think he is commenting on “good writing” in the sense of a novel or line of poetry.

Moby Dick is my go-to example of a novel that is incredibly well-written, but I wouldn’t say it’s particularly clear or straightforward in its presentation of ideas.

An example, if you haven’t read it:

”The path to my fixed purpose is laid with iron rails, whereon my soul is grooved to run. Over unsounded gorges, through the rifled hearts of mountains, under torrents’ beds, unerringly I rush! Naught’s an obstacle, naught’s an angle to the iron way!”

Maybe the first paragraph could have been written less sweeping?

I don't think Paul knows that he's writing rhetoric and not prose.

Imo, that quote is clearly a train metaphor. But to your point, I do vaguely recall being unclear plenty when I read Moby Dick decades ago.

True, this quote is just one of my favorite from the book and I wanted to share it. There are definitely other more difficult lines in it.

I find that Moby Dick passage to be quite clear and straightforward. It uses metaphor, but a simple and direct one.

Fiction still has ideas to get across and internal consistencies it needs to maintain to be enjoyable and get those ideas across.

When characters do things that beggars belief built upon their previous actions, it can ruin the whole story.

Even poetry has some truth and concept inside the poet to which it’s bound.