It didn't fail. It was marketed as a story driven MMO for casual gamers, and that's exactly what it was and still is. What failed was people expected it to come out with as many raids as WoW has, all expansions combined.
MMO players need to stop getting these unrealistic expectations of the game before it comes out. We saw it with WAR, AoC, SWTOR, GW2, and now we see it starting with Elder Scrolls Online.
The reason I enjoy this game so much is because I didn't follow any part of it. I wasn't even interested in the game until my friend gave me a beta key. I had 0 expectations when I first played it.