This is because Nvidia screwed apple (from Apple’s POV) years ago with some bad GPUs to the point where Apple flat out refuses to source Nvidia parts. I don’t know the internal details of course just the public ones so can’t say if Apple is being petty or if Nvidia burned the bridge while the problem was unfolding.
Given that the CEO was the supply chain guy at the time I suspect the latter, as I’d imagine he’d be more dispassionate than Jobs.
In any case I seriously doubt nvidia could, much less would benefit from cancelling Apple’s agreement.