Vector databases, from the major cloud providers

Why haven't the major cloud providers (Google, Amazon, Microsoft) already provided managed vector databases in their offerings? Faiss at Facebook is for example a very nice project. Is the market not big enough, or are there broader conceptual problems in AI that would make or break their utility? It seems fairly clear that learned rich vector representations are here to stay for the long term. Their interpretation, robustness and appropriate 'composability'(like transfer learning analogous to table joins) is very much in the realm of research, but this also means in the longer term a very rich set of logical as well as security control primitives (only Alice and Bob are allowed to see the footage of the police car making the donut stop).