Because in order for your agency to grow beyond what you're capable of, other people need some permanent motivation.
That motivation usually comes in the form of "ownership" and is never easily volunteered.
However, if/when it is will finally be the time you can focus on the core things you're good and grow the agency.
That's what I talk to my longtime friend Carlos Vargas, of Vargas and Vargas Insurance, about how much freed he got for part of this ownership.