What I'm missing about The Summer Book

Maybe it's me, well, it is me, but I still don't get it - am finding nothing of great interest in Tova Jansson's The Summer Book - a get it that these are series of sketches (some illustrated by her own pencil sketches), of varying degrees of interest about life on one of the small islands in the Gulf of Finland around what appears to be the first half of the 19th century - hard to know, in that life there is probably primitive and isolated to this day. One of the better sketches is one in which the grandmother and the child (10 years old maybe?), Sophia, motor out to the farthest-out island where a rich owner is building a large vacation house - grandmother in particular is very critical of everything about the place - she has that old snobbish mentality that change should stop at the time of her arrival (47 years back, I think she said) on the islands. Quite astonishingly, she and Sophia break the locks and enter the house - and then, surprise!, the owner pulls up in his motorboat. He invites them in for a drink - makes some disparaging remarks about the vandals who must have broken in - is very neighborly - but of course he knew they broke and and that they're completely contemptuous of him - but he never lets on - and Jansson never does either, in any direct way, neither S. nor the grandmother reflect on their visit or wonder if her knew they'd broken in - she only drops one sly hint, noting that the never returned the visit. Good sketch. Others, though, are good in a slight way: an account of a storm on this islands, for example. Others have just passed through my mind like water through a sieve. The whole book would be better, in my opinion, if there were some arc or shape to the narrative - Sophia's growing up over the course of a summer; over the course of many summers. An evolving relationship between her and her grandmother. Some kind of exploration of the distance of her father and the absence of her mother? Any sense of who she is as a person, what she does year-round, who her friends are? Sketches - yes, that's exactly what this feels like - not a finished work.