What is bigger- Zelda or Fable

[theRepublic]

Mr Khan said:

I'm going to channel the spirit of Khuutra, and in lieu of burning your face off with a death glare as he would have, explain that Zelda, historically, has gone through zeniths and nadirs of popularity. Skyward Sword is simply a downswing game, but there will also be future upswing games, whereas Fable is pretty clearly going in one direction.

I wouldn't even say those nadiers are even due to the games themselves.  If you look at the data, it turns out the magic formula goes something like:

First Zelda game on system = Great sales

Second Zelda game on system = Not as great sales

It has been that way since the series started.  Skyward Sword was just in the unfortunate position of being the second Zelda on the Wii.