I'm not arguing that the German system is bad, just that it is a very different product from what American universities sell. It might actually be a better model for America to provide higher education to more people at a better cost.

> As for TAs: yes we absolutely have higher-grade students doing teaching or scientific assistance at university, source: many friends have done this.

Neither of those are called TAs. The first kind is a graduate student lecturer, the second is called an RA (research assistant). One or more TAs for a large course typically helps the professor in running sections and grading homework, those two things being missing from most German courses (from my understand being told by my friend about his college experience in Germany; they might have homework, but it wasn't graded).