I opted out of being a Medicare "provider" several years ago. It saddened me, because I like working with seasoned citizens. However, they are now so accustomed to Medicare that the expectation that they should personally pay me for my time is anathema to many. Not to all, however. I have never refused to help a patient because of financial limits.
However, entitlements turn otherwise proud grey-haired adults into... what?
The last time I was accepting Medicare, they paid me around $70 for a lengthy office visit, less than my plumber charges me for the same thing. No disrespect for plumbers at all: I respect their skills very much.
But what really put me over the top was their paperwork. Being a sole practioner who donates 1/3 of her time to teaching and a charity clinic, I could never afford a trained "Coder" to do insurance forms for me for $65,000/year (or more).
Yet if I did the Medicare forms myself, I'd end up working for around $20/hr - spending more time on paperwork than seeing patients. Just check out the government manual for Medicare filing for doctors.
Bear in mind that a form-filling error is a potential felony. My plumber has no such problems.