Inbreeding... and a little incest

[Raynor]

more changeable than Elves are

I would say this is open to interpretation; the worries of the elves are less mundane.

Originally Posted by Letter #131

Their 'magic' is Art, delivered from many of its human limitations: more effortless, more quick, more complete (product, and vision in unflawed correspondence). And its object is Art not Power, sub-creation not domination and tyrannous re-forming of Creation. The 'Elves' are 'immortal', at least as far as this world goes: and hence are concerned rather with the griefs and burdens of deathlessness in time and change, than with death.

I think that the elves delighted in change, being masters of Art and given their highly creative nature:

Originally Posted by Dangweth Pengolodh, HoME XII

But to the changefulness of Ea, to weariness of the unchanged, to the renewing of the union [of though and sound]: to these three, which are one, the Eldar also are subject in their degree. In this, however, they differ from Men, that they are ever more aware of the words that they speak. As a silversmith may remain more aware than others of the tools and vessels that he uses daily at his table, or a weaver of the texture of his garments. Yet this makes rather for change among the Eldar than for steadfastness; for the Eldar being skilled and eager in art will readily make things new, both for delight to look on, or to hear, or to feel, or for daily use: be it in vessels or raiment or in speech.