Was it the the coaches and coordinators who designed the game?
Was it the owners and commissioners who promoted and funded the game?
Or was it the players who inspired kids to play the game?
Of course Id say it was the coaches and coordinators who refined and developed the schemes and philosophies by which the game we watch is executed.
So in that same vein I want to say the biggest influence on Rock (and all other music) comes from those men and women who take the Curt Cobains of the world and shape and mold their raw musical ideas into something they believe the masses will purchase.
Keep in mind the fact that Phil Spector wasn't just a guy with a checkbook. He is responsible for the style and sound of the acts he produced. Much in the same way you can pretty easily identify which of the Chili Peppers albums Rubin produced due to his distinct ideas on how music should be mixed and presented.
And why not Sullivan? Because he was just a TV host and had nothing to do with the finding and signing the musicians or engineering their "sound".
Although I can appreciate your point, I don't think I would necessarily agree with you here. To use the same vein of thinking for an example:
Who had a bigger influence on football, and/or inspiring those who want to play it? Wayne Fontes or Barry Sanders? By your argument, that would be Wayne Fontes, and I'm going to have to disagree.