> Most German universities also don’t have dorms, on campus amenities, erm, or often even campuses.
Most universities have some form of dorms, however they're usually wildly inadequate in numbers - but as most students come from the town or nearer region of the university and don't move across half the country they can live at their parents' houses.
As for amenities: who needs special "college amenities" here? Sports is provided by the town (public sports training grounds), its clubs (for team sports) and for really niche stuff sometimes by the universities themselves, drinking is allowed both in public and in a number of bars, discos and other venues... so what is missing? (Honest question, my knowledge about US campus culture is based upon more or less shitty comedy movies)
As for TAs: yes we absolutely have higher-grade students doing teaching or scientific assistance at university, source: many friends have done this.