[ainur]

A scholar could conceivably read "The Silmarillion" as a 'how-to' of greek-type tragedy with every archetypal tragic hero represented from Feanor, whose ego was the root source of all the tragic events that followed (and whose brilliance was the root cause of all the great deeds) to Turin whose sufferings never seemed to be his fault but were the source of his great deeds.
But what about Frodo?
Certainly he was capable of 'greatness' or he would never have reached the Cracks of Doom, despite Sam's help. The torment of the ring would have consumed a lesser mortal and yet he struggled on. But, ultimately, he failed. Literally on the brink of Doom, he declared the ring his own, and it was only Gollums lust for the ring that achieved its destruction, a fitting end for its evil. But Frodo's ultimate failure ended his life, the life he had known, as surely as a knife in the heart. More surely, for the catharsis of this climax is all the more poignant as we witness chapter after chapter of Frodo's demise into ennui--far more moving than his mere death would have been.