I looked at the code, installed a test site and read the Wiki. Is this project on a down low at the moment with only 19 commits and low activity since late last year ?
Also, when you mention that you manage to pay the bills with development of habari powered sites, do you draw from a community need for habari developers or are these clients that you persuade to use habari ? I'm curious about the overall community and where it's going.
In my work, clients mostly need a site built to perform a specific function, and if Habari fits that task, I use it. There isn't an explicit demand for Habari developers, but there is a high demand for sites that Habari is suited to produce, which overlaps a bit with WordPress' capabilities.
As others mentioned, the main habari/habari repo commit count is low because the main development doesn't happen there, but in a submodule'd repo, habari/system. The purpose of this is to allow you to easily fork the main repo to add your own plugins and themes to it, while the submodule continues to pull from the system repo. It's very beneficial from a maintenance standpoint.
I'm not sure how to explain the community. My involvement has been nothing but beneficial for me, and it has been a similar experience for the people I know the community has touched. Development has been reasonably continuous, as you can see here: http://www.ohloh.net/p/habari