As a Uni student, I still see people use Facebook, but it's a select group of people. It's the same < 5% of the people I interact with regularly. Most people I know use Facebook just for events so you can invite someone to a fundraiser or party.
On the other side, I see Instagram doing fantastic among my friends, and it gets way less hate from them, despite being very openly owned by Facebook (it says it on the splash screen).
Yes, but they use another "social app" that happen to be owned by Facebook the corporation. Even though I don't like Facebook and its founder, I have to say he was clever enough to avoid the fate of MySpace, which just stopped to be fashionable and died. Even if Facebook.com will start going down there is still Messenger, Instagram, WhatsApp that are still "cool".
Counterpoint: users already have moved away, and that's why advertisers are able to do this without hesitation now. FB is still growing in the third world, but I don't know a single person in the US under 30 that still uses it.