Willing, perhaps, depending on the product. Able, not necessarily.

This is not the case currently. People coming to the US from other first world countries for healthcare fall into two groups, rich people getting elective procedures, and people seeking a particular kind of cutting edge treatment that has recently been developed in the US and hasn't yet spread elsewhere. On the other hand, the numbers of people from the US seeking medical treatment in foreign countries has grown so large that it's become an industry. There are foreign hospitals designed from the ground up to cater to people traveling from the US to get essential procedures done. Health tourism destinations include not just developing countries like Mexico and India, but also first world countries like Spain. As I understand it, a foreigner traveling to a country that provides health care for its citizenry specifically to take advantage of it's health care system is charged for the care they receive, and even so it is often still beneficial for them to make the trip.