I think you are missing the point. It's not that interest in these things is what is essential to the old internet but that a shared interest and shared language is - and this includes as gp has pointed out metaphors and imagery.

But to your question, Tolkien, Asimov, Lovecraft, et al. are still a heavy influence on modern Fantasy, Sci-Fi and Horror. Why do you think a mere 45 years should mean that something is no longer referenced?