I cannot disagree with that. But the traffic has to be created from the start. These two sites came on the scene a little too late to get in on the act. There are already one or two, now well-known sites, where the traffic is continuous.
Another factor is enquirers response when they post a problem. It has to be quick, or they move on.
I was a very early moderator on these forums, and then, in good communication with the site owner. At the time it could be more than a day before a poster got an answer. Improved considerably now, but, my opinion, too late.