not, I would guess, an explanation to which Tolkien himself would subscribe.  Indeed I think Tolkien might question whether we ever really "own" anything at all, or whether, like Tom Bombadil, we are better off refusing to own anything.  Thus giving becomes not a mark of wealth and status, but a natural act of someone who never claimed ownership in the first place. 

Feanor's sin when he refuses to give up the Silmarils is not his lack of generosity, but his belief that the Silmarils are in fact his and his alone, when really the light he captured in them was never meant to be locked up in a vault. 

Bilbo, on the other hand, realizes that his so-called wealth is not really his:

"'There!' said Merry. 'That must be the stone that marked the place where the trolls' gold was hidden. How much is left of Bilbo's share, I wonder,
Frodo?'

"Frodo looked at the stone, and wished that Bilbo had brought home no
treasure more perilous, nor less easy to part with. 'None at all,' he said.' Bilbo gave it all away. He told me he did not feel it was really his, as it came from robbers.'"

This passage refers to the trolls' treasure, but it also refers to the Ring, and when Bilbo had trouble giving up the Ring he tried to justify it to Gandalf by asserting the right of ownership:

"Bilbo flushed, and there was an angry light in his eyes. His kindly face
grew hard. ‘Why not?’ he cried. ‘And what business is it of yours, anyway, to know what I do with my own things? It is my own. I found it. It came to me.’

"‘Yes, yes,’ said Gandalf. ‘But there is no need to get angry.’

"‘If I am it is your fault,’ said Bilbo. ‘It is mine, I tell you. My own. My precious. Yes, my precious.’"

But self-sacrifice is a far greater virtue than charity, for the charitable merely acknowledge that they own nothing.  Frodo does not just give away his wealth, he gives away his future life in the Shire, and is willing to give away his life entirely in order to save the Shire.  "Greater love hath no man than this, that a man lay down his life for his friends."  Similarly, Feanor's greatest sin is not his hoarding of the Silmarils, but the Kinslaying.

I disagree about Galadriel.  She is no dragon, hoarding what she does not own.  The Three great Elven-rings were not touched by Sauron, and are not in and of themselves evil.  But Galadriel did make an error, for all that she does to preserve the pristine beauty of Middle-earth is in vain, since the One Ring is not forever lost, and must be destroyed.  Well, not completely in vain, perhaps, for she does offer wisdom and gifts to the Fellowship, and to others throughout the Third Age.  Don't forget, for example, her role in Eorl's rescue of Gondor, or in the White Council.  But in the end all that she has built with the power of her Ring will be lost.

“I dislike Allegory - the conscious and intentional allegory - yet any attempt to explain the purport of myth or fairytale must use allegorical language.  (And, of course, the more 'life' a story has the more readily will it be susceptible of allegorical interpretations: while the better a deliberate allegory is made the more nearly will it be acceptable just as a story.)” (From Tolkien Letter # 131.)

Tips for posting in the Reading Room.