Even a lowly new grad engineer has to sign a lot of stuff when they take a job that forces essentially exclusivity to your work there. I cannot dabble in outside businesses within the same industry or adjacent industries.
CEOs argue that their job is tough and many hours and life consuming and that's why they get the pay, and yet there is a whole genre of tech CEOs who try to CEO 5 companies at a time..
Meanwhile you have CEOs front running their own company or treating staff from different companies as interchangeable. It's funny governors have been thrown in prison for example taking free renovations on their home in exchange for contract work with the state.
Not in California. Only company executives can be bound by such agreements. Direct competition is of course prohibited.