A common theme I notice in the question and the comments; respondents are not thinking globally or using numbers.
Just because in the US/Europe Facebook is getting bad press, or declining amongst young users, etc. doesn't mean that's the case in other countries.
The US isn't even Facebook's largest market anymore; it's India [1]. Sure, most money comes from the US/Candada region [2], but that's just now. As these countries' economies continue to grow the amount of money Facebook can make there will too. There's also strength in numbers; the US has around 300m people, the world minus China and the US has 5,400m others.
If you wanna make serious analysis you have to look at the numbers too. Facebook's active users worldwide aren't even stagnant; they are still growing at a fairly constant rate [3]. 2018 is not even close to being the end of facebook.
I see a ton of emotional and anecdotal comments here. The question itself is itself, I'd assume, based off the recent discussions here on HN and news articles around Facebook and Russia, and IMO written just to incite another hot Facebook thread since I'd assume anyone could guess that a $500+b company can't possibly die in 9 months. That's ok, but I am however surprised and disappointed by the lack of statistics and analysis though. I would've expected more from the HN community. I was hoping people here would like to stick more with facts, numbers and a rational view.
[1]: https://www.statista.com/statistics/268136/top-15-countries-...
[2]: https://www.statista.com/statistics/251328/facebooks-average...
[3]: https://www.statista.com/statistics/264810/number-of-monthly...