Computer controlled efi is the game changer. When you can pull 4,5,6 degrees off timing at peak torque and ramp in back in once the engine is past a dangerous detonation window then you can still safely make the power. And you have knock sensors to cover your bad tuning mistakes that used to end up in piles of piston parts. Could you make more with more octane? Sure but then it would t be pump gas anymore.