"You carry the fate of us all, little one."

[Imladris]

And most interesting to me (because I can't seem to reconcile it with my idea yet), why is it necessary for Frodo to lose the symbols of the other races and face the chasm naked and alone?

We must all fight evil, every single one of us. We can have help, but ultimately it comes down to us. Ultimately the individual decides whether he will give in willingly, or go down fighting. Nobody can help us with that at the bitter end. It is ultimately up to us.

Unfortunately, no one can win that battle, hence Frodo's defeat.

[Boromir88]

Unfortunately, no one can win that battle, hence Frodo's defeat.

Praise Gollum! For just happening to slip in and take the ring with him!

[Elladan and Elrohir]

No, praise Eru. Nothing "just happens" in Middle-earth, least of all the destruction of the Ring.

"Some other will than the Ring's was present. I can only say that Bilbo was meant to find the Ring, and not by its maker." - Gandalf, Book I, Chapter II

"No, chance brought me then, if chance you call it." - Tom Bombadil, Book I, Chapter VII

"I think this task has been appointed for you, Frodo, and if you do not find the way, no one will." - Elrond, Book II, Chapter II

"A chance-meeting, as we say in Middle-earth." - Gandalf, Appendix A