The (very thin) blog post said "Enhancing our retrieval infrastructure" - my guess is this is more about other forms of retrieval, like constructing and executing SQL queries and using the results to help answer questions.
This. Not sure why RAG triggers vector search for everyone. Retrieval Augmented Generation is as generic as it can get.
Looking at the landing page now it seems they almost pivoted into semi/unstructed data.
To your point, I feel like nobody knows exactly how to do RAG really well (fast and accurate). I also doubt the Rockset team has it figured out but it seems like there is an opportunity to build a new kind of database/memory system and OpenAI believes the Rockset team can help.
Google (Android, Gmail, Maps, G Office), Apple (iPhone, Mail, Maps, Productivity), Microsoft (Office365, Windows, XBox).
In terms of moat and lock-in, that leaves OpenAI vulnerable to last mile customer hijacking.