Most people, like me, who end up needing to use vector DBs, are wanting to use LLMs on a specific, often private dataset/use case. Typically one starts with something like unstructured JSON data, then need to pick and manage LLMs to create embeddings, then store these and the original JSON data in a vectorDB. Then the application is some variety of CRUD operations + searching over both the original data and the embeddings.

Chroma, Pinecone, I guess FAISS/HNSWlib/etc only handle vector operations. Really what I'd want, which Marqo does, is handle everything end to end.