I don't have insight on what goes on inside Google - they may well be doing this at some level, but their business isn't finding stuff, it's selling ads, so getting the search right is a very low priority.

The LLM people are heavily invested in ever bigger models to keep the research money flowing in, it wouldn't make sense to release a service that undercuts that.

that leaves independent actors - presumably building and maintaining an up to date database is difficult, so only the big search engines do.