[dragonwriter]

> Currently in the US the largest health insurance provider is actually medicare/medicaid.

Medicaid is more 50 different insurance providers (it's run by each state—with separate programs for, at least, D.C., Puerto Rico, and Guam, and it's not even a single insurer in every state, e.g., California uses a number of county-level managed care plans as well as a traditional fee-for-service plan.) And all of them are separate from Medicare. Which also is less of a single insurer with common coverage policies than it seems on the face (even excluding Medicare Advantage, which is just publicly subsidized private insurance), since whether any given procedure in reasonable and necessary and therefore covered in any given geogrpahical area in Medicare depends on local coverage determinations made by the private insurer that is the Medicare Administrative Contractor for that region and claim type (there are separate contractors, with different geogrpahical regions, for regular part A&B claims, home health and hospice claims, and durable medical equipment claims.)