I could be wrong, but it seems to me that the Three were visible after the destruction of the One simply because their bearers no longer hid them. I don't really think that the destruction of the One Ring itself, or the fact that it was "no longer the age of elves" or somesuch played a part in this. After the One Ring was destroyed, there was no longer any reason for the Three to be hidden, so the bearers of the Three ceased to hide them.
Remember also that when Sauron first created the One Ring, the bearers of the Three immediately knew Sauron's treachery, and the Three were said to have gone into hiding.
|