The profit margins are not the only thing. There are tens or hundreds of thousands of people working on billing jobs at doctors and insurances that shouldn’t exist.
And you think a government run system would be more efficient? It’s still going to have people in each side verifying claims, preauthorizing stuff, etc. To do otherwise invites massive fraud.
They're cheaper because of price controls on medications and salaries.
That's just straight up not going to happen in the US. We could have easily tackled medication prices by tying them to an average of some select other countries, but we haven't.
People would throw an absolute fit if our government tried to lower the salaries of doctors, and especially nurses.
The US is also just a very large country, population-wise. German has around 84 million people, so barely more than twice the population of California. I'd be a lot more likely to support government run healthcare if it was done by the states. The larger a system gets, the more inefficiencies sneak in - and, as a bonus, people could move to other states if the healthcare in their own wasn't up to par.
Government run is not the only alternative. We should start at standardizing and simplifying things. Less variations in insurance plans. Standard data exchange. Same pricing for same procedures. Price transparency. It doesn't make any sense that a drug or procedure costs less in cash than through insurance.