Would the public plan pay Medicare-level reimbursements and pass the savings on to enrollees in the form of lower premiums? If so, more than 131 million people might enroll, 119 million of which would have dropped private coverage. This translates into a market share by government-run insurance (Medicare, Medicaid and public plan) of about 80%. The market for private coverage would likely collapse if it had to compete against a near government monopsony with an 80% market share.

On the other hand, if political pressure prevented the public plan from tightly managing claims, the public plan could suffer from adverse selection and experience huge loses , which taxpayers might get stuck subsidizing.

Precisely because Medicare coverage has so many holes and leaves the elderly so vulnerable, almost all of them have to get Medigap and supplemental drug coverage — paying three premiums to three plans — and even then they don’t have the drug coverage most young people have.

So, no. Most people would not like to trade in the insurance they now have for Medicare!