correction. I should have said The U.S. has also had a weaker currency relative to the Euro.
It seems that Germany is a better managed country than the U.S. Perhaps that relates to having started over in the mid-twentieth century whereas the U.S. Constitution is an 18th Century document. Though amended many times, it is a seriously defective document for underpinning government of a 21st Century country. In particular the courts' interpretation of the First Amendment has led to all sorts of problems.
Two differences having huge impact on both the German and U.S. economies stand out to me. The first is the dramatic difference in military spending. The U.S. has been, of recent, spending nearly $4000/capita on "defense" once vet benefits and interest on borrowed money is included. If you leave off the later two items, the direct expenditure is about half that, at about $2000/ capita. Germany, on the other hand, is spending only around $300/capita. That's about an order of magnitude less than what the U.S. spends!
The second dramatic difference is in medical spending. German spending on health care per capita is less than half that in the U.S.; yet access to care and outcomes are both better in Germany. To highlight how significant this difference is one only needs to note that medical expenses are the most prevalent cause of personal bankruptcies in the U.S.
Curiously, both countries have a privatized system of medical care; both countries rely on private insurers. Both countries have highly regulated medical care.
It would seem that philosophy behind the regulation, however, is chiefly responsible for the dramatic difference in cost and outcome. In Germany the insurers are tightly regulated to keep costs down and the goal of the regulation is to achieve maximum social benefit and regulate competition in. It is clear that in Germany the regulated are not driving the regulation.
In the U.S., however, it is the regulated who are driving the regulation. The result is that competition is regulated out. The FDA plays a major role as well, and largely serves the pharmaceutical industry. The combination of these forces in the U.S. has resulted in a medical care Cartel and virtual absence of competition. As one would anticipate, the profits have been large --I believe, for example, the Vanguard Health Care Fund has the highest returns over the last 30 years of any of the Vanguard mutual funds. Profits and salaries at the top of the U.S. health care industry have been so outsized relative to the remainder of the economy that corporations hitherto not involved in health care are seeing opportunity there. Companies such as Walmart are now eying the healthcare Cartel as a possible source of new profits. Walmart's participation, of course, will be fought tooth and nail by the current Cartel members. The rallying cry, as always will be degradation of quality and public safety issues. In the long run though, costs may finally be brought down to a more reasonable level if firms such as Walmart can provide the sorely needed competition that will eventually break the back of the Cartel.
Not only do I see military and medical costs as two of the defining differences between the German and American economies, but I see them as essential targets if the U.S. is to survive economically and break out of the debt death spiral it has entered.