I think there are two parts to the answer. Firstly, health care in the US is extremely expensive. There are long articles written about this but IMO a main reason is market failure. The US, especially republicans, place a lot of value on free markets but people are willing to pay almost anything not to die.
The second part of the story is that the US is richer than Europe. I moved to the US from Western Europe. Before I moved here I didn't expect how much more everything is more expensive here, but at the same time salaries are also higher. The US's GDP per capita is $62k, Germany's is $47k. But that doesn't tell full story. In the US there is a big difference between low paying and high paying jobs, rural and urban areas.
The second part of the story is that the US is richer than Europe. I moved to the US from Western Europe. Before I moved here I didn't expect how much more everything is more expensive here, but at the same time salaries are also higher. The US's GDP per capita is $62k, Germany's is $47k. But that doesn't tell full story. In the US there is a big difference between low paying and high paying jobs, rural and urban areas.