Is there a name for this literary device?

It’s decades since I read the P. C. Wren books, but, as i recall, the books after Beau Geste filled in some of the blanks (often in flashback) using different viewpoint characters. So it was a combination of retaining a clear story line for Beau and leaving himself plenty room to create the backstory of later books without having to work everything out for book one.
If he had said it was an uneventful journey, or made no reference to exciting episodes, it would be more difficult for him to later set important scenes then without readers feeling that some sort of clue should have been given.

I don’t think there’s a literary term for this, because by definition, literary terms are used for things that raise the artistic level of the work. More likely, this would be classified under a negative term for laziness, poor narrative, bad editing, typo, etc.

What do you mean by “raise the artistic level”? There are lots of literary terms that are critical of the effect being produced. Here are a bunch of literary terms:

I would consider each of the following to be critical:

anachronism
anticlimax
bombast
bowdlerization
cliché
doggerel
hagiography

And those are just the first ones I found going through alphabetically, sticking to terms that I’m familiar with, so there are undoubtedly many others.

I think it’s actually a little more than letting the readers do the work. One of the main tropes of Lovecraft is that we humans, despite our supposed ruling of the planet, are really insignificant and powerless. Part of what makes the horrible things scary is that the fact they are indescribable, and therefore incomprehensible and uncontrollable. If something is so alien that we can’t even reach the step of being able to put words or concepts to it, then what hope have we of even avoiding it, much less controlling it?

How about the old mathematical favorite: “It is left as an exercise for the reader…”

Back then it might have been relatively unfamiliar to readers. Today it would be overly-familiar (and condemned as a cop-out).

Not if they were familiar with 1001 Nights. Statements like, “…was more marvelous than could be inscribed in the corner of a camel’s eye with a needle”, are pretty frequent.

It’s called Yadda-Yadda.

Well, there is the question of how many would have been familiar, up through the early 20th century. Given the infamous reputation (sex!) of Burton’s translation, for one, the Nights wouldn’t have been exactly nursery-room fare (not in English-speaking areas, anyway).

Also: not a novel. Possibly the standards we hold for “traditional tales” differ from the standards we hold for novels, attributable as they are to named authors.

The closest non-Seinfeldian term would probably be ellipsis.

The literary device is called “editing.”

For centuries, editors (employed by the publishers) were ruthless devils determined to cut a story down to the bone, and then to the marrow, to save publishing costs. A writer would submit a 1,000-page gift of literary perfection, and an editor would say “We’ll publish this if you can cut out 550 pages.” So the author was forced to remove important chunks of his (or her) work and say stuff like “but that’s not important right now” to the reader.

Over time, readers got tired of this, and rebelled. This gave the writers more power to leave things in and tell the editors to stuff it. We’re now at the extreme other end of this pendulum, as evidenced by George R.R. Martin being able to take 31 pages to describe the food and fashions at a wedding in the *Song of Ice and Fire *series, which is not about food, fashion, or weddings.

I’m not sure I agree, in that “editing” to me is more applicable to telling an author they can’t spend 30 pages describing the food in a novel which is not about a banquet, rather than saying “Pay no attention to the awesome thing happening here” as the reader is ushered past something like a giant octpus fight, daring escape from a castle, or epic battle.

Well it wouldn’t be infamous if it wasn’t famous. People might not grow up hearing the stories, but that doesn’t mean they can’t seek them out as soon as they’re old enough.