I'd like to understand this better. If I was a software engineer for 20 years and had cover and savings etc then was between jobs for a few months for whatever

I'd like to understand this better. If I was a software engineer for 20 years and had cover and savings etc then was between jobs for a few months for whatever reason and got into a car crash how would that work. Would I get medicare/aid? Are all people students / unemployed expected to be paying monthly premiums to get any kind of cover? I have had healthcare in the US for a serious accident, but I had travel insurance (UK based) which likely saved me 100,000s of dollars. Fortunately they paid up without question. I'm not sure how that would have worked if I was just some regular student from the US travelling around, would I be bankrupted for life or hoping for crowdfunding? Sounds like if you have an accident in the US you need to be rich or popular (or maybe really poor).