Your observation reminds me of Sarah Iles Johnston's analysis of Greek myths. (https://vridar.org/tag/sarah-iles-johnston/) -- The abbreviated character of them functions as an invitation for the audience to actively participated and enquire imaginatively into the stories. The Gospel of Mark is similar. So many loose ends and questions raised. Example: why is it that the first disciples called just seem to drop everything and follow Jesus? Surely we are missing some of the story. The reader has to think and wonder and fill in the gaps him/her self.
These prompts for the reader to ask for further information about this or that are the spurs that draw the reader/listener deeper and deeper into the story world. This personal imaginative involvement encourages belief. (At least it encourages belief among those who are willing and wanting to believe.)
Such half-explained details invite others (or even the same author) to add more stories to flesh out the original, or to add sequels and prequels to the original. If we take the apocryphal writings of Enoch et al as post-Pentateuchal, then we may conclude that such a narrative device has worked its magic most successfully.