We already have tons of hospitals, clinics, doctors, nurses, PAs, labs, etc. Insurance, Medicare, Medicaid, or VA already pay for just about everything. All we would be paying in addition are the idiots who skip insurance and then get in a major accident. Even those idiots end up being covered by Medicaid once their savings and house are gone.
So it can't possibly cost more than we are paying already. It has to cost less because we let insurance companies make 20% overhead, while those very same companies process all the Medicare claims for just 5% overhead. And make a profit doing that!
What they could do so there are no shocks to the system, is to just lower the Medicare age by five years each year. So in 2019, everybody 60 gets Medicare. In 2020, everybody 55. And so on.
One thing I'd really like to see is drug patent reform. Some drugs are making a 20000% profit, and it really makes Medicare expensive. Limit all companies to 1000% profit across all their drugs, or they lose their exclusivity rights. Then limit royalties they can charge the generic manufacturers to that 1000%.