Well, the problem with calculating like that is that you're using your own cost of health insurance and multiplying it. I can't tell for sure, but I'm almost 100% certain that you'd be paying significantly less than $4000 a year in a universal system.
Another problem is that there's dozens of ways to set up a national health care system. I'm not sure how it works exactly in European countries, but at least here, Health Care is jointly medical insurance and pensions plan, and the monthly "allocation" is shared three-way by employee, employer, and government [there's also private doctors, clinics and hospitals, for those who can afford it, but the quality isn't MUCH higher]. I think in other countries it might be totally free and paid for with taxes. And there's other ones. Can't say I'm an expert on the subject. But what I still fail to see any evidence of is why the cost would be so much more inexorbitantly higher in the US and in Germany or France or Japan. I mean, sure, the US has 300m people, but those countries combined have a similar population (like 260m) and similar GDP (13 trillion to around 10-11 trillion). More than welcome to show me, if there's any studies on the issue or any page that explains why the cost would be that much higher in the US.