Needing a new opening is like needing a new fighting stance. Is it the stance that wins the fight or the hits that land?
Both. Custamato taught Tyson to use two gloves cupped over his face with his elbows dropped toward the sides because Tyson is short and it allows maximum guard of his body while maximizing power. Tyson would be at a disadvantage using a Philly style guard because his broad build and stature would take away from his punching power.
Kasparov described Radjabov as one who hasn't learned how to play simpler positions as black, hence Radjabov's dependence on Pirc and King's Indian, and some players like open vs closed or tactical vs strategic positions and vica versa.