Less well known, but important to Mayo's early growth, was its principle of billing based on patients' means.
Fewer patients means fewer medical assistants, receptionists and staff members to deal with insurance.
One of them once told me: "Employing clinical experience to decide how to treat patients means continuing to make the same mistakes and never learning from them".
To make money out of employing large teams of highly trained staff with sophisticated medical equipment to treat high-risk patients means charging prices far beyond the reach of all but the seriously rich.
"They have a huge number of things that they're supposed to cover," he said, while pressure from insurers to see more patients means that "they're scrunching down to seven or eight minutes for a single clinical encounter".
The failure so far to reorganise services for such patients means too many are not getting proper care and can end up having largely avoidable spells in hospital, which adds to the pressure on A&E units and hospital beds and also wastes vital NHS resources.
