Those fees have no drop out, if the semester ticket had a drop out I guess nobody really wants to do that. You get to use all public transport of the region for a very low price. (Only exemption is, when a student goes abroad and can't use it anyway it the student can be exempt, usually there is also the possibility for poor students that the ticket is paid by the student body. At least we had the possibility to do that)

The other part is the Studentenwerk (Student's Works) which runs cafeterias, housing and other services which you can use for a low price or even free.

The third part is for the student body. In most states in Germany the student body is an legal public body. It is used by the student parliament den the student committee (AStA) to fund services and other stuff which is needed to represent students and their needs. Usually the semester ticket is not made between the university and the transportation company but between the student body and the company, therefore the AStA is negotiating the contract about it. (depends on the university).

We also had three permanent employees, which helped a lot.

Insurances of any kind is not included.

Full disclosure, I used to be the chair of a student committee of the student body of an German university.