OK, but making money, though it may be less than a PE company would, is. Where do most doctor's offices fall?
Simple example pitch that many general practitioners might consider using (based on local laws, of course):
“Insurance covers C, Y, and Z. I can offer these additional services for A, B, and C that are not covered by insurance.”
Where I live, you get a lot of this via “concierge doctors”, but that system can go far beyond basic concierge service, and people are willing to pay for top quality care.