That's a pretty retarded statement in it's self. Floyd isn't the biggest, fastest, or strongest, boxer on the planet. What makes him the sport's best P4P fighter is his out of this world boxing IQ.
Fair enough. To be honest, it's possible that Broner was including the mental side of the game when he was talking about how only certain special folks could become boxing champions. (Though I doubt it -- Sounded like he really wanted to talk about "blathleticism", actually.)