Zero people from other nations come to the US to save money on health care. The ones that do come are looking for specialists for some exotic condition, not because they love the level of care or the price tags.
And do you think those specialists would exist here if we had medicare for all? no, evidence: all those other countries that have that and no such specialists.
This is a great point more people should make. There’s nothing “America first” about preserving the inefficiencies of a system just so that very wealthy people from everywhere can get care and leave (and ultimately specialists would anyway still exist, even if their treatments aren’t covered by Medicare)
if everyone had that specific knowledge, there would be no specialists. no, different countries develop different specialties. famously, Kobe Bryant went to Germany (a country with national healthcare) to get a knee procedure from a specialist.
It's not a one way street, though. Americans go to other countries like Canada or Cuba for health care, including, famously, GOP Congressman Paul Ryan.