They are pretty much at the tipping point where the signal to noise ratio has gotten so low that it seems futile to add more signal. There is also a component to it as well where is it really worth it to give FB even more data about my life?- what am I even getting in return for it these days? And even more recently, I woke up one morning recently and the feed felt really stale, I was seeing posts from the previous day. I tried to look at just my friends, and then sort by most recent, and you could see that just the number of people actually posting what they are up to is just way down.
Instagram is better for this these days, but its headed in the same direction it seems.
The context in which you share stuff is incredibly important. If the platform will bookend your posts with crap, it reduces the value of your own post.