I have to disagree with this; a senior developer will produce more value if not completely ignored; if involved with the company, they can then not only help steer the technological direction of the company, but also move tech towards the company's future goals, not the company's current state.

If left undirected, they will still move tech and be productive, but not necessarily in the direction the company wants to go.

It was a joke! The joke being that senior developers get interrupted a lot by business people and junior devs.

Many managers produce negative value!