1) U.S. healthcare spending subsidizes the rest of the world, much like U.S. defense spending. New drugs wouldn't be developed at the same rate if it wasn't profitable to do so, and it's profitable largely because it's profitable in the U.S.. Some proportion of the high U.S. spending relative to other countries is this. It's pretty stark. In revenue terms, for new drugs 2018-2023: 67.1% of total sales in the USA alone, 15.8% in Europe, 3.9% in Japan, and 13.2% for the entire rest of the world ( https://www.efpia.eu/media/2rxdkn43/the-pharmaceutical-indus... )

2) I believe the U.S. is willing to go to greater lengths to save people. So they will spend obscene amounts of resources keeping a cancer patient alive for an additional six months, or saving a borderline case of a premature baby, etc.