Ecotrain and NM really do work to encourage engagement as much as possible. There are a couple of people who will pull us all up if posts get missed for engagement. 😉 It helps that there is a growing group of people who are really passionate in those areas.
DIY is one of those things that is great to have as a go to for a broad range of people, but often it's something that they look up when they need it rather than it being a regular passion. Hopefully as more passionate DIYers come along the community will get more active.