It depends on how much they are willing to keep it alive by teaching this. Some of the writing techniques already died out because it was getting hard for people to learn it. We don't use old english anymore such as the writing style from shakespeare because it is too difficult to understand for many people. I think once it becomes too difficult and nobody wants to learn it it can eventually die down but not entirely out!

They are disappearing yes. This is because the schools here only want Mandarin to be taught and used in class. Dialects are now only spoken at home, that's if both parents speak the same dialect. 

Children have told me they don't speak the dialect because they want to have better Mandarin and don't think their dialects are important. It's sad to see children not keen no learning dialects because they think it's not important ...