I'm not sure how else we can tempt them. There is little audience for them compared to the likes of a giant such as Facebook and their community groups. Look at the numbers of members in that image.
It's staggering to see how many people are interested in such a niche hobby as the one I write about so much.
These groups can be big and that is why we need to work on bringing some to Steem. Maybe better to start with more technical people. I would have expected the open source world to show more interest in Steem.