Subject: Re: impractical promises?
Medicare for All is a single payer system, and it's not only possible but it would significantly reduce the overall national cost of health care. The transition would not be easy, with deeply ingrained interests and highly corrupt lobbying by those interests. But that shouldn't change the goal. The implementation would probably be gradual - starting with a drop in the Medicare eligibility age to 60, and perhaps also covering all children up to age 5, and then maybe closing the uninsured gap by another 10 years every couple of years. It's difficult, but it's possible and beneficial.

It's not possible, and it wouldn't significantly reduce the overall national cost of health care.

We pay a ton of money for health care because we pay a ton of money for health care. The administrative costs of private insurance are a very, very small amount of national health care expenditures - barely a few percentage points. So switching how we pay for health care doesn't create much savings. In the meantime, extending the coverage of the average health care policy to: i) all the uninsured; and ii) all the people who have below average health care policies will blow up our health care expenditures even more.

Nor is it possible to do what you're describing. You can't incrementally expand the Medicare eligible population, because your new actuarial pools will unspool even before they form. You have to offer them coverage with a premium of at least the average cost of coverage for a 60-64 year old. But then, all the people who are sick will join the Medicare program (because their expected costs for the coming year will be higher than the premium, so it's a good deal for them), but all the people who are healthy will stay out of the new pool (because their expected costs are lower than the premium, so they can do better elsewhere).

Single-payer systems avoid this adverse selection problem by forcing everyone into the pool at once. There's no option. Medicare solves the problem by forcing everyone to pay into it for all their working life, and then when they hit the eligibility age they are offered insurance with a premium that is less than 20% of the cost of coverage. It's an offer they can't refuse. But you can't do that with the new 60-64 year olds - no one's been paying into the system for their entire life to cover that extended pool, and without being offered that unmissable "80% off" discount you end up with your adverse selection issue.

You also end up with a problem on the provider side, because Medicare pays less than private insurance. So if you take X% of private patients and move them from the private insurance pool to the public pool, you're cutting the amount of money that flows to medical providers. Some won't make the switch over, which is problematic for patients; others will make the switch but it will blow a hole in hospital and clinic and other institutional budgets, which is problematic for everyone involved.

Unless you raise taxes. By a lot. If you raise taxes by a lot you can offer the 60-64 year old group the massive subsidies that will induce healthier patients to join (like the ACA extended subsidies) and keep reimbursement rates high enough to induce providers in without blowing up their budgets and cover the cost of the uninsured that now have access to health care. But, of course, raising taxes by a lot is unpopular.

There's no avoiding the economic pain. And since everyone knows where this is going (switching everyone to Medicare), everyone will react to the proposal knowing that it's a total switch even though it's phased. So it's a political impossibility.