Facebook is getting grown out of. The younger ones hardly see FB as the hip thing.
And, FB has morphed into more than just a way to meet friends. It has become the town square for the village idiot to shout at the top of his lungs as to how UFOs are implanting DNA into the cattle.
I think Facebook has gained an almost utility-like status among the general population. Sure, you might not be on it as much as you used to be a decade ago, but most people still consider having an account on it as useful. Facebook really saved itself by having a thriving Marketplace and various local groups. There's also many entertainment/meme pages, but there's plenty of competition for those.
I myself hardly ever log in to my account and haven't even posted anything on my "wall" (remember when that used to be term?) in nearly a decade, but I still find myself visiting the Marketplace whenever I need to occasionally buy/sell something or find a new apartment.
Sure, teens and kids are using it, but it feels like people will grow out of it.