This is mostly to obtain cheaper care. In general America does seem to have some of the best care in terms of quality. It’s just also some of the least affordable.
US is not the only destination for Europeans, they also go to Thailand and wherever. Few Americans go to Europe. It's not affordable, but when money is not the issue you go to the US.
i'm one of the Americans. went to South america for a dental procedure that was 12k in the US, 2.5k there. very modern facilities, they had some better tech than my american dentist. if you can speak a bit of spanish, i highly recommend looking into it for expensive dental stuff.
https://www.amjmed.com/article/S0002-9343%2818%2930620-X/ful...
This is mostly to obtain cheaper care. In general America does seem to have some of the best care in terms of quality. It’s just also some of the least affordable.