This is a reward for past performance, not an incentive for future performance.
I’m sure that Tim Cook was already extremely wealthy prior to this, to an extent that would exceed any capability to spend it on himself.
So now that he has an additional 750 million dollars, what is his incentive to continue performing?
He needs another 750 million dollars? For what? Is he supposed to be excited that he might receive some other ridiculous sum of money for which he has no realistic use?