Good questions but I would respectfully challenge some of your assumptions. Many, if not most health concerns present insidiously as we age, not necessarily a crisis but may require ongoing care. You can return to the US for this type of care but you do need local access abroad for care for accidents, strokes, heart attacks etc. which is available. Many countries have much more affordable care than the US and comparable or better quality including much of Europe (especially Spain, France, Germany, Italy and Portugal), Costa Rica, New Zealand and Australia. Some require establishing legal residency but that’s a hurdle that many expats have cleared. I have no plans to leave but I have friends without dual citizenship or relatives that have and they have successfully made the transition. It’s all about expectations.