Dr. Zuger writes about how they thrive:

Doctors without patients: can such creatures really exist? Or do they automatically negate themselves into some other sphere of existence, a cloudy existential plane where teachers without students and merchants without customers all wander around in search of a new identity?

It is a purely rhetorical question, because not only do doctors without patients exist, they thrive. They top most heaps: they are the administrators, the professors, the chairmen, the directors and the chief executives.

In fact, if truth be told, little baby doctors often go to bed at night thinking, I want to be just like them.