There's already a hedge fund where an AI has a board vote on acquisitions. This isn't that far out of reach.
Also ML/AI isn't even near strong enough to make the varied decisions necessary to run a publicly-traded company, but it could augment decision makers with recommendations.
CEO's start the company and suffer share dilution. They did their job if the shares are valuable.
Future CEOs don't get the same incentive package, and need something somewhat comparable.
Is it fair that society lets someone keep so much money? Maybe not. But if you are an owner (directly or through stock) or even an employee who de facto wants the company to succeed, it is mutually beneficial to have such highly compensated executives.