There are many pages in these forums devoted to healthcare reform. In this particular thread, until now that you have asked for my opinion on expanding medicare, I have steered clear of the many options for reform and just steadfastly maintained that we must do something, and that if we don't we are finished as a first rate nation.
Medicare-for-all has been on the table in the past, and it would be the most "natural" transition for the U.S. among all the single payer options that have been considered --or pseudo single-payer, because private insurers are still involved via medicare supplements. This in itself would not bring down costs, and that's where the problem lies.
The medicare administration, as you know, is blocked by Congress from operating efficiently in a way that would greatly reduce costs. It is all about preserving profits in the private sector. Medicare isn't allowed to negotiate drug prices, and they certainly would not be permitted to buy drugs directly from the Indian, Puerto Rican and Irish plants where they are being manufactured, though that would reduce costs in some cases from dollars to pennies. Even drugs under patent can be obtained for far less outside the U.S., but it's officially illegal to do so. With the present medicare system a person can easily be left with a 20 to 40K (or more!) bill after a brief hospitalization if they have no supplemental coverage, and supplemental coverage is expensive because both hospital and doctor charges are much higher in the U.S. than elsewhere. Medicare is not responsible for outrageous U.S. medical costs, but neither would it bring down costs by much if extended to everyone as its constituted now.
There is so much money to be made from the present arrangement that it is extremely difficult to get any kind of change that would actually bring down costs by much because of all the vested interests. Just look at the opposition to Obomney care. What we ended up with was what you would get from an unruly committee -- somewhere in the middle between wonderful and awful. We will get more people covered. But the cost is going to remain outrageous even if it comes down some. Ultimately it is cost that is out of control, and you can't bring that down without some vested interest making less money.
I've always said that my preferred way to tackle the cost problem would be to introduce competition and deregulate, because that way the market, rather then some bureaucrat, decides who is going to make less money. But the more I think about it, the less likely it seems that's a reasonable possibility. As time goes by, I am more and more leaning toward accepting that medical care is something that does not fit, and can't be made to fit, the capitalist mold with a satisfactory result.
What's interesting is, that based on the other industrialized countries we compare ourselves to, there is an extra 1.4 trillion dollars bouncing around in the U.S. health care system every year. That means that were we to drop our per capita costs back to the average of the other thirteen nations, there could be as much as 1.4 trillion dollars bouncing around in the economy that would then end up in different pockets then it is ending up in now. That's really the crux of this entire medical care issue.