If a program lowers the % GDP that is due to healthcare costs and raises life expextancy as well certain other stats such as cancer survival rate, etc. then it is just smart economically.
Let's put aside the fundamental difference right now about "Rights" versus "benefits".
Let's look at the numbers. But wait, we have no numbers! Do we have precedence? yes, we can look at another government run virtual monopoly versus the meager free enterprise alternatives (education). What can we see from that? Government's pay somewhere in the neighborhood of $7,000 per student to educate them. Private schools, about half that. So what makes everyone think that the cost is going to go down? (Initially it probably will, but what government program has ever come in at or under stated costs?). And standards to measure? Seems that Private education excels in that area too.
Next cancer survival rate and life expectancy. What empirical data does anyone have that shows these would improve? And before we trot out other countries, we do have to factor out the differences, do we not? So comparing the USA to Sweden, we first must take into account the immigrant population (much of them illegal in the US) that comes into the USA with pre-existing health care issues, and no prior health care. Then there are factors like accidental (this includes intentional as in murder) deaths, coverage area (the US is a big place with some places not served well), and diversity of population. I have looked, but have yet to find any studies that take these factors into account. So we have to compare apples to apples, and yet we have no apples yet.
So lets say - for good intentions - it comes about and the government nationalizes 17% of the economy (sounds like Venezuela - BTW how is their health care, life expectancy and cancer survival rates?). And your wish list of reasons does not come to pass (a possibility and since unknown, lets just suppose). Instead, costs go up, and quality goes down (as has been shown to happen in other nationalized countries of health care) - it is government after all - when has a government program not done this. What do we do then?
Has any failed government program ever been eliminated?
Once you get on the back of the fox, you have to hope you make it to the other side of the river before you wind up in his stomach, as there is no place to get off before the end of the journey - one way or another.