When you consider how smiths across Tamriel can make ebony armor. Then when you think how easy it is to mine then surely it doesn't take a genius to work with it.

Daedric however is a whole new ball game. How in the world of Nirn did someone randomly discover this skill without being taught it from a higher being? Especially when it only seems to work with ebony.

I never heard of ebony being all that easy to work with, much less common among blacksmiths in Tamriel. The Dunmer had close ties to the daedra, and had the largest sources of ebony around. Not surprising if daedric arms came to them at some point.

To go a bit farther with what Dargor said, I would guess that some Dunmer smith got a hold of some daedric armor from a dremora or something, and was able to reverse engineer it, and figure out how to make some.

A master conjurer got their binded Dremora Lord drunk, and thus the secrets were spilled.