...would be with analogy. Upper management don't do everything themselves. They have staff they delegate to. Get them to stop and think what a nightmare they'd be in if they had nobody to delegate to, and had to do all of the work coming at them by themselves. It's the same for IT.
If they try to go "But those other 5 guys..." stop them and point out that that would be like giving them 5 janitors to delegate to. They'd be better than nothing, but not the right fit for the job and a lot still wouldn't get done.