Most of the top universities in the US are effectively free. The pool of students they get to choose from would enter with a basket of scholarship money to the point they wouldn't have to pay. The other group is so wealthy the price of tuition is the cost of a new luxury car, every year. Effectively a single percentage expense.
Germany doesn't have to make their schools to compete free because the schools they compete against are basically free to the type of students they are pursuing.