This is the slow break down of society. Let's not cheer that on, shall we.
I don't believe the behavior you're describing actually falls along generational lines, though, rather than technical competence or awareness. It isn't only "teens" who use social media, nor is it only "old people" who are concerned about privacy. In fact, younger generations are leaving Facebook and social media because of privacy concerns and the negative effect it has on their lives.
Your arguments here are stereotypical ageism and lack enough nuance to be convincing.