Yes, I get your point. There are always few good ones available. But to earn a decent amount one has to spend a good amount of time abd have a few ones in hand. Many have restrictions with number of posts, daily limits etc. That can be another discouraging factor.
I am not sure with all the time and effort and all the potential and possibilities to maximize my earnings on these forum sites, if I could ever earn enough go provide a decent living. For me with all financial obligations that I have, I can't foresee that happening.