[Edited November 29, 2012, mostly to remove anti-civ axe-grinding.]
Lord of the Rings is the most loved book of fiction in the English speaking world, and also the most influential, having spawned the massive imaginative movement that we call the "fantasy" genre of fiction and gaming. This is only the beginning. Shakespeare's works, like Tolkien's, were considered commercial trash by his contemporaries. Now some credit Shakespeare with inventing the consciousness of modern Western civilization. At the very least he saw it coming. I suggest that Tolkien created/translated/anticipated the human consciousness of the world to come, the real world that will follow the long-awaited implosion of industrial civilization. We have been thinking of Lord of the Rings as an "escape" from the "real" world into a mythical past only because the dominant mythology of our time, which is truly an escapist fantasy, told us so. I suggest that not only does it make sense to talk about a Tolkienesque future, we're going to go there.
Now the first question everybody's asking is: What do you mean? Will we have elves and hobbits and orcs? That's vanishingly unlikely but not impossible -- if the present system holds on a while longer, it may genetically engineer new human-like creatures of different sizes, shapes, and talents, and each variety would tend to get together and become an autonomous people with its own culture. But even without biological diversification, if we free ourselves from controlling powers that make us all the same, we will develop a spectacular variety of cultures and societies -- even more diverse than before civilization, because of the influence of surviving technologies. With enough freedom, somewhere there really will be people who live in treehouses and hunt with bows, and somewhere else people who live in houses dug out of hills and practice sustainable farming. And in a less than ideal future, "orcs" and their rulers will exist as a survival or reemergence of the present system, trying to murder or enslave all other life and concentrate hierarchical power.
Will we fight each other with swords? Again, it's possible. But it would be better to remember (in that world and in this one) that deadly fighting is fun only in stories and games. In the real world it's horrible and ugly for everyone involved.
Will there be magic? Of course! The only recorded belief system that doesn't accept anything like magic is the Cartesian mechanistic paradigm, in which everything is a lifeless object and the scream of a tortured animal is no different from a bell ringing on a machine. This metaphysics is stupid from every perspective but its own. But because most of us are still inside this perspective, it's hard for us to imagine what "magic" will be like. All I'll say is that, in every belief system outside the industrial age, matter is a feature of mind and not vice versa.
And, in this magical Utopia, will the dominant nations be hereditary monarchies? Will there be zero public sexuality? Will certain races be biologically good or evil? Will we seek happiness by identifying what's bad and destroying it? Here we can notice that J.R.R. Tolkien, one of the greatest geniuses who ever lived, might not have understood some things as well as we do, and that we can take what we like from his writing and leave what we don't like.
Or can we? The conceit that we can just pick out the parts we like from here and there, and force them together into a perfect whole, is the same kind of thinking that got us into this mess. We don't get to sit back and engineer the world -- we shape it by living in it; and we don't get to pick exactly the features we like, because the features themselves have likes and dislikes, motives and alliances and disagreements.
Not only that, but all the people who love Lord of the Rings, from pagan anarchists to Christian fundamentalists to Italian fascists, project different values onto the book and would try to create quite different Tolkienesque futures. Still, these visions have something in common. Lord of the Rings may not describe the future literally, but it points at it emotionally, through modernity to the world beyond like Bard's arrow through Smaug's heart in The Hobbit. And like the five armies fighting over Smaug's treasure, everyone who knows that the beast is dead will be fighting for a share of what it was hoarding.
But as Tolkien knew, the larger world is not hostile or mindless, and it's not an accident that the nastier Tolkienesque futures, and the unworkable ones, will tend to be the same. For example, if we took the Lord of the Rings that the fascists like, and put it in a real world, then the "good" elves and dwarves and humans would exterminate the "bad" orcs and goblins, and then they would continue the same habit against each other, until only one humanoid race was left, and then that race would cover up the evidence that the other races ever existed, and invent new "races" within itself to feed its killing habit.
From this angle, Lord of the Rings is a vision of the past after all! (And it's uncannily similar to a lot of non-dominant history and archaeology.) Another silly interpretation is the one that glorifies medieval weapons and technology. The medieval world was a passing stage in a history that has now given us many more options.
But Lord of the Rings is big enough to be a naive longing for the past and an inspired vision of the future -- and an intelligent appreciation of the past. We can learn from preindustrial humans and primitive humans, but I don't think we're going to go "back" to living like our ancestors, but forward, full circle, to a reinvented undomesticated world, a world that's raw and untamed and alive, not because it's innocent but because it's experienced. And Lord of the Rings describes it in subtle but specific ways:
The whole universe and everything in it is packed with intelligence and meaning. Other creatures are as smart as humans and will talk to us if we know their language -- even trees! When cultures are not conquered or controlled, they become extremely diverse and creative. Societies that expand and exploit resources ruin everything, but they always fall. People will live among the artifacts and ruins of forgotten civilizations, but will not try to follow the same path. Cultures will adapt to the land they live on, instead of forcing the land to fit them. Though people belong to a region, they may still adventure and travel. The world is made of stories, not facts; it is not known or knowable, but merges away into endless mystery and surprise.