I think most politically minded people consider FB to be an unethical company. On top of dwindling user numbers, FB might be on its way out if they truly think people will be okay with this.
On the other hand, tons of people use Instagram now, which is undoubtedly why Facebook is trying to further integrate it with Facebook.
As others have mentioned, there are products of Facebook that are doing really well. I think that the use of Facebook as a generic social media feed is dwindling, but it's still good for niche groups, classifieds, and probably other things I'm not as privy to. However, I believe this is because there isn't a sufficient replacement for what Facebook provides. Are there any alternatives to Facebook that provide similar features but aren't considered distasteful by the mainstream?
Their acquisition of Oculus (and its FB account requirement) isn't hurting either. I also hear their groups/classifieds product is doing very well.
Unfortunately, Facebook isn't going anywhere anytime soon.