All things considered, that’s still a small number of people to be in charge of. The staff at Johns Hopkins neurology appears to be less than 100 people.
Still, the staff alone is 20 times more than DoughtyOne’s estimate of 5 people, and he had other duties besides the neuro staff. Plus, executive ability is a learnable skill apart from numbers. Many MBAs get out of grad school and step into jobs managing hundreds or thousands at age 24. The numbers under management make a difference, but not an absolute difference.