Sounds like a scam - only poor immigrants will want to “retire” in the USA.
I see things working in exactly the other way. Increasing Gov’t take-over of US health care is going to encourage more medical tourism to cheaper countries with first-rate medical facilities for those who can pay (such as Thailand or India). Higher taxes, inflation, and any further taxes (not to mention nationalization!) of retirement assets will encourage any retirees with money to move someplace that will not penalize their assets.
You would not have to go that far. Here in Iceland, with the devaluation of our currency and the free market liberalization of our health system along supply side lines, you can get state of the art, highly educated medical service quite cheaply. We are situated in 8 hour flight from Florida and its old people ;)
It is becoming easier now when the government has split the government run part of the health care into service provider and service buyers, so the providers work like a private enterprize having to charge according to cost estimates to the service buying government agency for all work. And they have to compete with the substantial and increasing private health providers that also sell their service to the government.
And patients here are cost conscious as they always have to pay for a portion of the service, at least up to a point.