I know he saves the hobbits from the barrow-wight and gives them weapons which affect the Nazgûl, Sauron's greatest servants. But I've always wondered why a high power, which Tom Bombadil obviously is, doesn't play a more significant part against Sauron. Gandalf says at the Council of Elrond that Tom wouldn't understand the struggle between Light and Darkness.
Asked if Bombadil might take the Ring for safekeeping, Gandalf replies:
"No," said Gandalf, "not willingly. He might do so if all the free folk of the world begged him, but he would not understand the need. And if he were given the Ring, he would soon forget it, or most likely throw it away. Such things have no hold on his mind. He would be a most unsafe guardian; and that alone is answer enough."
The Fellowship of the Ring, Book II, Chapter 2: "The Council of Elrond".
What confuses me is that if Sauron regains the One Ring, Tom will also fall like the rest of Middle-earth.
Is there any other info in the texts (aside from fact that Gandalf says that he basically doesn't care what happens) about why he didn't play a more prominent role?