Counter point. Most of salary is decided based on how much of a loss it would be if you left. A CEO leaving a company can immediately lead to serious consequences whereas an individual employee can leave and no one might bat an eye
This is not to say I don't think CEOs do any work. They may make major contributions in terms of developing strategic plans, communicating them to staff and inspiring them to carry them out well, negotiating with allies, outmaneuvering competitors, and balancing the conflicting imperatives of operations, finance, security, legal and so on. But they're not compensated for labor so much as given (via negotiation) a commission on profits, revenue, stock price movement or suchlike. Inevitably there are conflicts of interest with shareholders, staff, and customers, and as a class CEOs and other high level executives seem to have tilted the tables more and more in their favor over recent decades.
Is it something that has been study or observed? Most company are resilient enough to handle the leaving of an individual, being a Chief or not. The opposite would be a flag for an instable company.
Far tangent exemple: Belgium without government.