One thing that is notably absent in Middle-earth is any mention of temples, churches, priests or religious rites. There are passing mentions of Men who would "worship" Sauron, but generally the world of Middle-earth seems much less religious than medieval Europe, or even classical antiquity. One never hears about "the cult of Aule" or "the cult of Yavanna," although historically there were many "cults of Athena" or "cults of Poseidon." Aragorn doesn't (to my memory) make an offering to Tulkas before battle, nor does he pray to Eru Ilúvatar for victory, and all the holidays and solemnities seem to commemorate historical figures, not religious ones.
This is especially strange in a world where there are still living witnesses, like Galadriel, to the actions of the Valar and other "divine" beings, and where there are still Maiar wandering around talking to people and putting on flashy firework shows.
Now, a lot of people talk about how Tolkien didn't want the Valar to be considered "gods," but at the same time he did use phrases like "the gods of old" numerous times. Clearly, these beings would have qualified for worship in most cultures. And even without the Valar being considered a true pantheon, there is still Eru, a closer analogue to the Christian God of Tolkien's beliefs, and we know the denizens of Middle-earth knew of him (Him?) because of the line "Eru, who in Arda is called Ilúvatar." And yet, Ilúvatar seems not to be terribly important to anyone on a daily basis.
So my question is this: how familiar with the "theology" of Middle-earth were the citizens of Middle-earth? Would the average merchant in Rohan know about the Valar and the Maiar and Iluvatar and the Music of the Ainur? The average noble in Minas Tirith? The younger Elves, like Legolas? The Dwarf Lords?
Were the theological truths about the formation of the world, the Valar and the Maiar just so well known that they weren't worth commenting on, or had they been forgotten by most? And if they had been forgotten, why wasn't the knowledge (whether through deliberate teachings or casual conversation) re-invigorated by witnesses like Gandalf or Galadriel?