I often come across statements like this:
Generally speaking, Sicilian endgames tend to favour Black for structural reasons. The extra center pawn and the half-open c-file are both advantageous for the second the player.
This is surprising to me, as I've also read that queenside pawn majorities are good in the endgame (e.g. in papers about the Grünfeld defence). I thought that the central pawn majority would rather give Black an advantage in the middle game, because there are still more pieces that need to be actively placed near the center. The queenside pawn majority however entails the potential to create a passed pawn that is more remote than the passed pawn that Black would be able to create using his majority. Why would the endgames be good for Black in the Grünfeld, but not for White in the Sicilian? If Black's central pawn majority in the center is advantageous during the middle game and the endgame, why isn't the Sicilian not just better for Black (after White's initial initiative has been fended off)?