[Aratlithiel]

After thinking about this for a minute and having just finished reading 'Letters' it has come to my attention that Frodo did NOT fail. According to Tolkien, to cast the Ring into the fire was an impossible task for anyone in ME - ANYONE. No one really expected Frodo to be able to do it - they only knew that of anyone else in ME, he was the best hope. Frodo's SUCCESS was in his pity for Gollum which later enabled the Ring's destruction. In other words, Frodo assured the success of the quest way back on the Emyn Muil - not at the Sammath Naur.

Which answers the question of who else could have completed the quest - the answer is nobody. Think of anyone else in the Fellowship - each one of them (with the exception of Gandalf who would not touch the Ring)would have cut Gollum down without a second thought - even the other hobbits. Frodo was the only one capable of the pity that was essential to the success of the quest. Therefore, Frodo was not only the most logical choice - but the ONLY choice.