[revelation]

Teaching students and teaching in general is time not spent writing that paper that gets you your PhD / postdoc job / tenure. Eliminate as early as possible to make sure 1) the load from incompetent students does not potentiate and 2) to spend more time with & recognize the ambitious students that you can recruit for free work on your PhD / postdoc / tenure paper or as TAs if your department is rich.

Also, in Germany, university is free and publicly funded. There is only a small incentive for universities to pass as many students as possible and almost none for the immediate professors and doctoral candidates that do the teaching. Alongside with the public funding comes the implicit understanding that not everyone, for whatever reason, is meant for a college degree and so 40-50% of certainly engineering related students will drop out. No biggie, you are not 150k in debt, just do an apprenticeship.