It’s second-hand info so take it with a grain of salt, but I read somewhere that there was a lot of friction between Apple and Nvidia because Apple likes to tweak and tailor drivers per model of Mac and generally not be wholly dependent on third parties for driver changes, but that requires driver source access which Nvidia didn’t like (even though they agreed to it for quite some time — drivers for a range of Nvidia cards shipped with OS X for many years and those were all Apple-tweaked).
It’s second-hand info so take it with a grain of salt, but I read somewhere that there was a lot of friction between Apple and Nvidia because Apple likes to tweak and tailor drivers per model of Mac and generally not be wholly dependent on third parties for driver changes, but that requires driver source access which Nvidia didn’t like (even though they agreed to it for quite some time — drivers for a range of Nvidia cards shipped with OS X for many years and those were all Apple-tweaked).