Bedrockgames
I post in the voice of Christopher Walken
IIRC Tolkien was in one of the World Wars which inspired a lot of the story for LotR. Then the Counterculture of the 60s gave it quite a following. I doubt that it will be nearly as popular with younger generations to come.
Tolkien is still incredibly popular and influential (in large part thanks to the film trilogy). I don't think there is any reason to think it will be less so