One area I see why FB is losing a lot of users is that there's just too much noise generated, where the content which people may find to some degree useful is being crowded by the same repetitive ads, notifications, (fake) news and headlines that are being circulated around within your interests (friends, followed stuffs, etc.).

I recall when FB was immersive because it provided you content which you relate to - people you know, people you follow, interests that makes you feel that this social tool is enriching your life. Nowadays, FB is like a river with too much garbage on it. You won't enjoy swimming, much less even enjoy what you are seeing.