I'd rank LOTR with something like Spenser's Faerie Queene. A great deal of wisdom and perennial relevance permeates its pages. Some readers will not get past the fairy-story form, but if they do, some will be able to discern that this is a work that deals worthily with great themes and permanent values. It is, of course, a superlative work of the imagination, satisfying (to many) as a place to go to, but from which one also brings back much. It is a life-enhancing work. It is great art.
To the degree that it seems to become "irrelevant," that will often, I think, be an index to a deficiency not in the book but in its reader or in the culture in which readers are embedded.
It may be read simply as "escape" from reality, but many readers will find it provides escape to the reality of permanent values. It is a noble book. In an ignoble age, one may expect to see it disparaged. (I'm not referring to things that people posting here have said.)
It relates somehow to two things I have taped to my office door.
From Film-maker Werner Herzog:
"The volume and depth and intensity of the world is something that only those on foot will ever experience."
--LOTR must be a book that has launched a thousand, or a thousand times a thousand, walks.
Theodore Dalrymple, in "Compliance with Untruth" in The New Criterion:
"In my travels in the communist world... I came to a realization about its propaganda, at least for internal consumption, that was, perhaps, pretty obvious, though not immediately to me. It took a little reflection on my part to come to a conclusion that no doubt will seem to you utterly banal: namely that such propaganda was not intended to persuade, much less to inform, but to humiliate. For this reason the less true it was, the better, for by not only forbidding contradiction to its claims but demanding assent to them, the human being's sense of independence and worthiness as an individual was destroyed from within, as it were, gnawed away until it no longer existed. The more preposterous the claims and the more obvious the defects in reasoning, the more effective they were, especially for intelligent and educated people. And this process of human destruction, perfected as never before in the Soviet Union, is now far advanced in Britain and I daresay in the rest of the Western world."
But LOTR, alertly and thoughtfully read, is an anti-propagandist work. It is about people who connect with perennial truths in order to make hard choices only they can make. One is example is the heroine of the book, Galadriel. For thousands of years she has ruled an Elvish realm (that, yet, cannot last), in Middle-earth, having refused to go into the West. Now Frodo freely offers her the Ring. By it she could become great indeed and effect in Middle-earth a whole world of beauty and timelessness... at least for a long time. And she looks within herself, this near-goddess, and turns down the Ring. Instead she equips a couple of hobbits to throw it away. From one point of view, after Galadriel does this, everything else is details. She saved the world. And hardly anybody in the book, so far as we know, ever even knows what happened then.