That format shift is exactly the mechanic. Summary-first structure isn't just reader UX — it's how you get your passage into the top-k chunks that actually reach the model's context window during RAG retrieval. The chunk that gets cited is usually the one that answers the query in the first 2-3 sentences, standalone, without needing surrounding context to make sense.

The news sites doing this probably aren't optimizing for AI citations intentionally — but they're converging on the same structure anyway because it works for skimmers and for models. Same underlying reason.