Yeah, but such places are pretty hard to get into. Most places you can actually hope to live permanently aren't first world.Most first world countries, you should very definitely expect US-level care, or better, certainly for urgent care/ER visits.Medicare is useless overseas. You would have to make your own insurance arrangements. Do not expect US-level medical care!
Travel insurance normally only covers emergent situations, not chronic ones.Most such places have insurance automatically for taxpayers, so if you're allowed to work, you're probably covered - but the rules vary a lot from country to country.
If you're not covered in that way, insurance is typically FAR cheaper than it would be in the US. Typically healthcare is covered by travel insurance, (as long as you're not going to the USA).