The sci-fi keywords are all specifically space-related. I wonder if the trend is space-specific or if other sci-fi topics suffered the same fate (like robots, computers, technology, etc). It does seem to me like society generally became less interested in space exploration after the moon landing (though I wasn't around then so that is really just what I gather from watching/reading things about western society in the latter half of the 20th century).

On the other hand, fantasy includes vampires and werewolves. I guess you could call them fantasy but to me they are quite a different niche to Tolkien. Traditionally vampires and werewolves would probably be considered horror rather than fantasy, though it's a bit more complicated now as Twilight is clearly not horror.

I think the author's point stands regardless, as there has been a resurgence across all of those keywords, but I do think the reasons for the resurgence in magic and dragons aren't necessarily the same as the reasons for the resurgence in vampires and werewolves.