> But there are plenty of soap operas on private networks, too. We would not lose anything if they would stop producing those [...] private companies, which would create the same service.
Which is questionable at least: Take Lindenstraße for example: I personally dislike it but without question is has been on the forefront of bringing important topics to the TV screen and probably the most diverse cast of all soap operas produced in germany. The english wikipedia page only has a short paragraph, read the german page if you can: https://en.wikipedia.org/wiki/Lindenstra%C3%9Fe#Cast Notable example are showing homosexuality in 1986, the first homosexual kiss in 1987 (the actors received death threats as a consequence), ... No private soap opera in germany dares to touch sensitive topics. American soaps are a bad substitute.
I also agree about theater and opera, though the tickets for those aren't cheap and you don't get a free ticket just because you paid for public broadcasts.