Its that nvidia relentlessly works with game developers to make sure their graphics tricks work with nvidia drivers. Its so obvious you miss it. Look in the nvidia driver updates they always list games that have fixes, performance ect. AMD never (used?) to do this they just gave you the drivers and expected developers to make their game work with it. The same strategy that MS used for their OS back in the 90's.
Thats at least how things got where they are now.