I would agree that too much focus on "quality" content (whatever THAT is, by whatever metric) will tend to be a limiting factor, on the whole. Most social media isn't about that.
What might be more important is whether or not something adds "value," quality or otherwise. In other words, when you post something, does anyone else want to look at it. If "yes," then it adds value, if "no," then it doesn't.
Why does "adding value" matter? Well, who the heck is going to join a site that doesn't have any content anyone wants to look at?