You are absolutely right about that--for at least the next five years.
I would argue, however, that the current mainstream culture is unsustainable. The death of manners leads to a death of people caring about each other. A lot of people don't want to live that way.
At some point, enough people will start seeking out subgroups where some manners and respect are followed that the subgroups will start influencing mainstream culture.
Right now, the mainstream culture will beat up any subgroup that tried that. If a school told young men to wear suits and girls to wear dresses for graduation ceremonies, for example, it would bring a round of bad publicity and lawsuits. Even a clergy member who told people to dress and behave properly in his or her house of worship would probably get a lot of criticism.
But if enough people get sick of the death of manners, the subgroups might start standing up for one another. At that point, mainstream culture will change somewhat.
What did Emma say about Audrey?