Boards that try to delegate authority to staff often worry that volunteers will lose commitment. It's a realistic concern: volunteers who handled large responsibilities under the board do sometimes decide, when the board passes the management baton to the head of staff, that they are no longer needed.
This used to surprise me. Why would restructuring the flow of authority cause energy to disappear? Why are volunteers who take high-level responsibility under the board respond to the board's delegation of authority to the head of staff by taking a vacation? I'm no longer surprised, because I've found that maintaining volunteer commitment while moving management from board to staff is pretty much a universal challenge.
The solution, luckily, turns out to be fairly simple: the staff needs to learn to ask people to take big responsibilities as volunteers. For some reason, there's often a mental block against the head of staff (or a department head) saying to a proven volunteer:
Here is an area of work I'd like you to take charge of. Would you consider serving for a two-year term as Director of ________. You would not be paid, but you and I would set goals and meet on a regular basis, and you would be included in staff meetings as appropriate. I think of this as the equivalent of a quarter-time job. It is a lot to ask, but I am asking you, and I hope you will say yes."
In larger congregations and nonprofits, staff leaders often have such conversations. Sometimes the volunteers say no, and sometimes they say yes. People have always taken big responsibilities as volunteers. There's no reason they should stop because the board decides to get out of management so it can concentrate on governing.