A single page that addresses only the seed query is positioned to answer one branch, at best. The other branches get answered by whichever pages do address them, regardless of how well the original page ranks for its main term. This is the practical reason a narrow page can rank well organically while being almost entirely absent from a generated answer on the same topic.
Pre-answering the likely branches inside the same piece of content, rather than spreading them across separate thin pages, gives a single page coverage across more of the fan out at once. This is the same logic behind building genuine topical authority rather than one isolated article per keyword.
None of this requires guessing blindly at what the sub questions might be. The pattern tends to repeat across a topic: a definition, a mechanism or process, a comparison against alternatives, and a qualifying detail that narrows the answer for a specific situation. Structuring a page around that pattern, with each part properly developed rather than a passing mention, is the practical version of writing for fan out.
This is also where content marketing and on page structure meet directly. The work is not about adding more text, it is about making sure the angles a real reader and a fan out system would both expect are actually answered somewhere on the page.