I don't think the problem should be approached from a "great market" perspective. The market for Hacker News is quite niche. Yet, it has become a great community for the curious of us. Almost hardly replaceable by any of the communities/websites who have great market potential and wider audience. So niche is probably a good thing here.

Driving a critical discourse (on something like Health or Hacker News) between scientists, journalists and the general public can potentially create more appreciation for scientific progress (which might often be dull and slow indeed) and provide a feedback loop for how science is/should be communicated or even done.