The reasons Americans live shorter lives despite being much richer than their peers are well-understood at this point, Cremieux explains:
The biggest contributor is that obesity is very bad for health, as countries get richer their citizens tend to get fatter, and America is the richest country.
[…]
All Americans regardless of race are, in principle, exposed to a health care system of the same quality understood broadly, although there are gaps in access, but those access gaps don’t fit the order of the longevity gaps—as a close proxy, in 2024, the insurance rates go Asian > White > Black > Hispanic. These race results and the sex ones combine to produce a picture that cannot be explained by a simple health care-centric story. In fact, when it comes to things the health care system can plausibly intervene on, America is usually the highest-performing country—at least cross-sectionally—or it’s very nearly so. When it comes to lifespan and America’s lag despite its riches, look elsewhere than health care.