https://www.commonwealthfund.org/publications/issue-briefs/2...

> OECD Health Statistics data show U.S. registered nurses (RNs) earn 1.5 times the OECD12 average salary. These data are adjusted for purchasing power parity. Using numbers of RNs in the U.S. from the Bureau of Labor Statistics,22 we computed total RN earnings using average U.S. pay and OECD12 average pay. The difference was $79 billion, or about 2 percent of 2021 NHE, representing approximately 5 percent of excess U.S. spending when rounded to the nearest multiple of five.

It's not nothing, but it's hardly the only reason, or even a particularly big one.