Immortality

[obloquy]

The existence of Elves: that is of a race of beings closely akin to Men, so closely indeed that they must be regarded as physically (or biologically) simply branches of the same race. The Elves appeared on Earth earlier, but not (mythologically or geologically) much earlier; they were 'immortal', and did not 'die' except by accident. Men, when they appeared on the scene (that is, when they met the Elves), were, however, much as they now are: they 'died', even if they escaped all accidents, at about the age of 70 to 80.

Morgoth's Ring - Athrabeth Finrod ah Andreth

I thought that quote might be useful. Here's another similar one:

[Finrod] remains, nonetheless, in the opinion that the condition of Men before the disaster (or as we might say, of unfallen Man) cannot have been the same as that of the Elves. That is, their 'immortality' cannot have been the longevity within Arda of the Elves; otherwise they would have been simply Elves, and their separate introduction later into the Drama by Eru would have no function.

Morgoth's Ring - Athrabeth Finrod ah Andreth

From this it appears that the Elves and Men were separated in nature by nothing more than their respective 'fates'. The perceived nobility of the Elves was likely more due to their history and lineage than any inherent property of their being. Their 'magical' arts were no doubt simply a result of their thousands of years of study and practice, their close connection with nature, and their relationship with the Ainur. Men would probably have had the same abilities if they had had the same history. As it was, their history was more one of darkness than light.