I think there's so many ways to connect on the internet that every social app has it's own role and purpose. Everything is fading away as users age and their preferences change. On top of that there are always new apps which are trying to attract new users and lock them in until something new doesn't come out that's why Zuck was obsessed with competition. He tried buying Twitter and Snapchat but they refused on the other hand Instagram and WhatsApp gave in.