I have to admit, just when I thought facts about US healthcare couldn't surprise me anymore, I learn that astronauts - one of the toughest and highest profile government jobs you could have - don't have guaranteed healthcare later in life? That seems insane, especially given there's really not that many astronauts out there to begin with.
I'm from a country with public universal health care, with a private option (i.e. you can pay for private health insurance on top of the public system if you think it's worth it - it covers extras like dental, cosmetic surgery, etc.) But private insurance isn't tied to employment. You just buy it from a company like you would car insurance or home insurance. Having said that, the public system is good quality (you'll probably be treated by the same doctors either way), so there's no need to worry if you can't afford it. It's not a perfect system but it's gotta be better than what's happening in the US.