Because a CEO is a specific thing with a specific meaning that just isn't relevant here. It's laden with human meaning that is irrelevant to a statistical model.

Really you're trying to say that the bots coordinated their efforts, and perhaps one of them was delegating tasks.

This type of structure is very common in tech, in load balancers or queues of service workers, containers and hypervisors, et cetera.

Power structures that seem logical and efficient to humans are not so for a gen AI model. If everyone knows what needs to be done and no one has any ego or character traits to manage, then everyone can simply perform the next task as it arises.

Its absolutely absurd to suggest that the bots elected a CEO.