If client relationships are jeopardized by the loss, there may be costs to rebuilding them. The same with relationships with suppliers and credit sources. All of these factors are multiplied when the Thousandth Man is the owner of the business. They see what happens when they are gone for the day or the week, and their solution is to never be gone again. But not all absences are a matter of choice.
Some owners die while they are still active in their businesses.
A greater percentage become disabled in a way which forces them to withdraw from active participation. The rest eventually do retire. The withdrawal of the owner is not a contingency but a certainty. The only uncertainty is when it will happen. No matter when or how it happens, that transfer must be designed so it does not cripple the business.