There's "catastrophic injury/health" insurance in the U.S. You just don't get it by default. I did a bit of research into the topic in the past and my takeaway is that if you buy the right insurance packages you get pretty much the same coverage in the U.S. that you'd get here (Germany) except you have the option not to do it. From what I gather it's also not that much more expensive, I'd argue the quality of care in the U.S. is probably better (it's pretty high in Germany but the U.S. is probably the #1 in the world on average) and the service quality for someone with this kind of insurance package is better for sure (longer waiting times in Germany for certain procedures/issues for example). All of this is assuming you're lucky enough to have a decent job/salary (which we are as tech people).

I guess it looks more grim for the "lower end of the spectrum" in the U.S.