I do think however you got the last bit wrong, Squidy. JRRT was not a time traveller, but a psychic. Clairvoyant to be more precise. He also had the ability to communicate telepathically with other dimensions (parallel worlds) and saw the developments there, that were not unlike those about to happen in this world. He saw the similarities and he wrote them down in this clever fictional disguise. So we don't live in Tolkien's Middle Earth, but in a second version of that Middle Earth. This is why Tolkien disregarded the allegory idea. Because it's not about allegory, it's about alternate realities. Get it?
Where's the proof, you'll ask? Well, didn't he say he merely
recorded all these things, not invented them? Sure, with all you nonbelievers out there, he had to take this back in an end, but I bet he was muttering under his breah 'e pur si muove'.