How much plot material can a novelist afford to squander?

I was kind of surprised that in the 2nd part of Jane Gardam's Old Filth we come back to a scene involving both OF and his lifelong rival and now, late in life, friend and neighbor and confidante - his weird name is Veneering, I could not remember that name in previous posts - only to learn that Veneering is now dead, leave OF alone again as a character. How odd - I would have thought Gardam would want to build to some kind of scene, a confrontation or a confession (V. had carried on a very long-term affair with OF's wife, Betty), but oddly she doesn't - she's a very strange novelist indeed. As noted previously, she builds this novel, a portrait of the life of a successful if "ordinary" Englishman, through scenes out of sequence, and gradually the picture comes together, like a mosaic - but I'm surprised that she scorns plot to such a great extent - why would a novelist piss away her chance for a really good scene, perhaps the capstone scene to the entire novel? (Well, maybe she works that out later - as the novel is out of sequence - so she could come back to a confession - though I doubt she will). OF at this point in the novel is alone, Veneering's next-door house is being torn down or rebuilt or something and a family is moving in - England changes - and there's a scene in which the children next door find some "old beads" in the garden - we known (OF does not) that these are valuable pearls Betty buried there, I think on the day she died - also improbable. V. encouraged OF to write his memoirs - these chapters are not his memoirs, none is in first person - but we see in these chapters the material for the memoirs that he is unable to pull together. We gradually learn a little more about his terrible childhood - some of which he recounts to V. - and we're building toward learning about how he became engaged in WWII - the ship that was evacuating him to Asia turned around and brought him back to England, as the Asian ports had fallen to the Japanese apparently. It's not clear, yet, whether OF ever saw his father again, after more or less being abandoned in infancy. I hope he does. Won't Gardam give us at least that much? How much plot material can a novelist afford to squander?