I envision what is already happening to LinkedIn, that is that less relevant content is shared, in favour of personal stuff (e.g. pictures of vacations), political opinions, etc. Basically the transition from "let's talk about x" to "let's talk about me".

I still get contacted by recruiters for jobs, so it's useful to me, but I agree that is becoming more and more annoying. I don't know what can replace it, but I suspect that any platform replacing it would go down the same facebookization/instagrammization path.