Or maybe Facebook is still doing fine since there is no good enough alternative. It seems like Facebook is getting worse all the time but since everybody's there and it's familiar people still uses it. Indicators are they are losing young people, who tend to adapt faster and have not yet build habit of use and more and more people are using other services for particular activities.
Still there is nothing which could totally replace Facebook so old users are staying and baiting new users. It still has unique offer for large user base and very useful features so even if it's getting worse it can stand. People might be clicking their feed more but that's because they are so bored with content that they try if they can find something more interesting behind the links. Or they are scrolling down since trying to find something interesting, something different which is hard since algorithms just push same boring content all over again. But statistics look good.
What's the magic of Facebook? If you could answer that and build the service people will flock out from Facebook.