A more serious way of putting it might be that the US is in raw dollar terms one of the richest countries in the world (certainly by far the richest large one), yet in many ways (infrastructure, quality of administration, political culture, etc.) it feels more similar to a middle-income one.
"The richest poor country in the world" might be closer to it. As the rest of the threads under this post will reveal, we mostly agree that something is wrong with this country — but putting our finger on what that is can be challenging.
But healthcare? 50th percentile US healthcare is pretty good. It's 25th and under who get shafted.
Having a higher median income is all well and good, until you find it all eaten by education, healthcare, and transportation costs... In addition to less financially denominated costs. 
But eh, if you didn't need to take care of your kids, or yourself, you could theoretically afford more iPhones.
 Having lived in Canada, and the US, I can't put an exact dollar value on the stress of, for example, having to deal with the American healthcare system, but its non-zero.
It's a new sort of poverty, affluent and insecure at the same time, and it's probably not a stretch (given the content of the article we're commenting on) to say it's bad for health.
The average Dutch citizen might take less money home, but they also work 30% less, they won't face the threat of not having healthcare or a roof over their head, and they don't need to inhale car exhaust on a highway for an hour per day but take the bike instead. More money is evidently not the solution to everything. American society seems to be optimised around creating economic activity for its own sake.
edit: not really sure what the reflexive downvotes are for, the links between precarity, inequality, stress and biological harm in populations are well documented, see Sapolsky: https://www.scientificamerican.com/article/how-economic-ineq...