That's why so many American doctors accept offers to practice in Australia where they receive a salary and nobody is dealing with billing. Many more choose the closer option of workng for a salary or contract work for an HMO like Kaiser Permanente.
Just because you're a Doctor doesn't mean you want to run a business, or that you're a good business manager. Conversely many of the best medical managers migrate to that position because they were not very good at being a doctor.
On the other hand, some Australian Doctors set up private practice for the 18% of Australians who have private insurance. But they have to be prepared to bill Medicare, plus the private insurer, plus the patient. These private practice Doctors typically have a salaried position at a hospital in addition to their part-time private office.
Some private practices deal exclusively with cosmetic procedures not covered by Medicare or insurance. Being an elective procedure they collect up front before they begin.
Many American doctors try to emphasize this type of business but not enough people want botox and fillers injected into their face to go around.
We've run out of other people's Social Security taxes needed to subsidize our low income tax rates.