This is one of my critiques also.

The more niche Tribes and Communities start popping up though, the more I think we will be able to find content that people off the chain are interested in.

For example, we've only just set up the naturalmedicine.io Tribe, and already we have started attracting readers who are not on Steem.... the next step is to get them to sign up for their own Steem accounts and start participating (and we're working on it).