The Elves represent, as it were, the artistic, aesthetic, and purely scientific aspects of the Humane nature raised to a higher level than is actually seen in Men. That is: they have a devoted love of the physical world, and a desire to observe and understand it for its own sake and as 'other' - sc. as a reality derived from God in the same degree as themselves - not as a material for use or as a power-platform. They also possess a 'subcreational' or artistic faculty of great excellence. They are therefore 'immortal'.. Not 'eternally', but to endure with and within the created world, while its story lasts. When 'killed', by the injury or destruction of their incarnate form, they do not escape from time, but remain in the world, either discarnate, or being re-born.
This becomes a great burden as the ages lengthen, especially in a world in which there is malice and destruction (I have left out the mythological form which Malice or the Fall of the Angels takes in this fable).
Mere change as such is not represented as 'evil': it is the unfolding of the story and to refuse this is of course against the design of God. But the Elvish weakness is in these terms naturally to regret the past, and to become unwilling to face change: as if a man were to hate a very long book still going on, and wished to settle down in a favourite chapter. Hence they fell in a measure to Sauron's deceits: they desired some 'power' over things as they are (which is quite distinct from art), to make their particular will to preservation effective: to arrest change, and keep things always fresh and fair.
The 'Three Rings' were 'unsullied', because this object was in a limited way good, it included the healing of the real damages of malice, as well as the mere arrest of change; and the Elves did not desire to dominate other wills, nor to usurp all the world to their particular pleasure. But with the downfall of 'Power' their little efforts at preserving the past fell to bits. There was nothing more in Middle-earth for them, but weariness. So Elrond and Galadriel depart. Gandalf is a special case. He was not the maker or original holder of the Ring - but it was surrendered to him by Cirdan, to assist him in his task. Gandalf was returning, his labour and errand finished, to his home, the land of the Valar."
I put in the paragraph breaks and the blue text is what I posted before. What I get from this is that for the world to change was God's will and for the Elves to refuse that change was going against the will of God just as the quest for immortality by Men was against the will of God. So why should the Elves be 'better' than Men if both were going against the will of God?
I have trouble with your basic premise that Elrond cares only for Rivendell, and nothing for the others... and this line of argument is not answering that! The Ring is the only victory that matters... and that one was in his living room.
They weren't, insofar as the Elves did this. Remember that not all the Elves were involved in this: the Great Rings were made by the Noldor. The Sindar had nothing to do with it. But notice that all the Elves paid a dear price for the creation of the Great Rings: Sauron empowered, Eregion destroyed, the corruption of other races via the Great Rings they made: and after all of that, they still weren't really able to stop the process of fading as they grew less relevant to the world as time passed. A decidedly mixed bag, IMO.
Elves were considered better than Men because, as a race, they were unfallen, whereas Man, as a race, had Fallen. Thus we see that for Men, it is the exception that are great and noble, not the rule. Among the Elves, it is the exception that are base and evil, not the rule.
Tuor