If they appear to work now, it's because the SEO leeches haven't found them yet. If they ever become popular, they'll get inundated with garbage too.
But LLM's don't really do that. They take the shape and context of your prompt and respond with a corresponding shape of text.
But im sure there's some hybrid in the works that will be very helpful soon.
I'm not sure I follow, those hybrids exist today, I mentioned one of them. They tend to fire search queries, extract the content over multiple hops and inject it into the LLM prompt for evaluation and summary.
Why I have never heard of perplexity.ai
Just tried it, so good and fast.
Not to sound like a total shill, but if you subscribe they let you switch the underlying llm to GPT-4 or Claude-2, which gives it some more oomph on more complex reasoning tasks. The free model is already quite good for research though.