The medical profession today is about where the engineering profession was at the beginning of the last century.

Then, they, like doctors, would put out a shingle and invent for clients.
Along came the modern corporation and as patents blocked other patents and the economics of the field changed.

This is very nicely illustrated in a book called "America by Design"

That book and my father threatening to disown me if I pursed a medical career were largely responsible for my pursuing other directions.

And, yes, you are right, mid-level managers in health maintenance organizations are making more money now a days than physicians.