Elves are being from "The Time Before". They are the first race, given Divine Knowledge from the Gods to do their will. Well they are finished with those Gods. It is hard to tell if they rebelled, the Gods were destroyed, or the Gods no longer can interact with the world. Either way Those Gods are no longer part of the world. That leaves The Elves to be their own masters.
Elves are superior to Humans in many ways. That is the nature of their bodies. They are immune to natural forces and the elements. They do not suffer from Disease or Old Age. They seem perfect in their nature.
They are all master craftsmen, master archers, masters of the staff, master musicians, and seemingly perfect at most things. Well that is not true. They know how to do these things well, improving with practice.
Elves are born with knowledge - everything they need to know, they are birthed with. Their history and lineage is wired into their very souls. The Elves are smarter, faster and generally better than Humans. They easily master their arts and crafts because they know the basics. So why haven't they taken over?
The Elves cannot learn.
They cannot speak the human togues. They cannot create new tools (though the tools they use are elegant). They can not trade for new ones (trade is a skill they never needed befor the rise of the humans). They cannot handle the way humans can change the enviroment to suit their wills, while the elves suffer the seasons in their gracefully weaved branches. They have no new artistic ideas, they merely draw to represent the world (in a beautiful style that predates time). They have no philosophy or science, as they just know.
They are creatures of stagnation. While they are masters of the skills they have, they fear the younger race's will one day surpass them.