Final answer:
Christopher Tolkien likely omitted some of J.R.R. Tolkien's writings from The Silmarillion to ensure narrative coherency and adhere to his father's publication intents, similar to a bibliophile curating contents for a comprehensive, yet cohesive collection.
Step-by-step explanation:
The question refers to Christopher Tolkien's editorial decisions regarding the construction of the posthumously published work The Silmarillion, which contains writings by his father, J.R.R. Tolkien. As the question does not provide specific details from the source material given, it's not possible to accurately say why Christopher decided not to include all of his father's writings in the Silmarillion. However, in the broader context, Christopher may have omitted certain writings to achieve a coherent narrative, due to overlapping content, or to honor what he believed were the intentions of his father concerning which stories were ready for publication.
LibreTexts mentions how the contents of the Miscellany for Sultan Iskandar were chosen, implying that like Iskandar's bibliophile tendencies, Christopher also had to be selective regarding what to include in The Silmarillion to best represent his father's literary legacy. This curation often involves a careful selection to include works that create a cohesive and comprehensive whole, without overwhelming with extraneous details.