CEOs aren't that busy. That's what they hire people for. The most successful people aren't running around like maniacs all the time. They are organized, they delegate, and they focus. How much of your day is spent actually working? How much is spent on pointless meetings, status updates, and busywork? CEOs don't have to waste their time on other peoples' priorities. Board members work far, far less. To them, it's the CEOs that look like they're busy all the time.
It’s still possible to delegate a lot of the CEO day to day stuff and be available for all important directional and strategy stuff.
Co-CEOs is also a thing.
Having half a talented persons attention is better than zero. Whether they should still be the show piece CEO vs the background mastermind is up for debate though.