As I mentioned elsewhere, there's more to vector database selection than raw performance: Developers leveraging their existing experience with Postgres, existing infrastructure investment (often in managed Postgres on AWS/GCP etc), and a single API into the vector store shared with other parts of their app (their ORM / DB layer).

Many teams can also get away with good performance vs the fastest performance, given smaller index sizes and the other tradeoffs I mentioned.

That said, I can imagine the pgvector folks precaching the new HNSW index support they're working on, as they do with their IVFFLAT index.

* edited for the grammar gremlins