Because the stage that is easiest to act on is also the stage that is easiest to measure in isolation, and the two facts compound into an industry. Rewriting a page is something one person can do in an afternoon without touching infrastructure, so that is where the advice concentrated. Measuring a rewrite is easy if you hand the model a fixed set of documents and vary only the wording, so that is where the early experiments concentrated. The result is a large body of genuine findings about what happens to a document that is already in the model’s context, generalised into claims about what happens to a page on the open web.
The 2026 critical survey of the field draws the line in its own confidence table. That a document already placed in the context can causally alter its rank, citation or use is rated high confidence, annotated with the note that this evidence “does not address organic retrieval”. That a white-hat intervention durably improves organic discoverability across multiple engines is rated low. That citation scores predict clicks, conversions or revenue is rated very low.3 Almost every disappointment in this field lives in the gap between the first row and the other two. The how AI search works stage is the pipeline this diagnostic sorts against.