"The role of "cultural sustainment" is key here. What is the draw (i.e., why does one want to participate? what is the proverbial "honey vs. vinegar" or "carrot vs. stick") to a coherent, collective atheist world-view? An intellectual satisfaction is not enough--it does not sustain nor replace the concept of "soul" or the emotional void that sits at the center of our humanity. The concept of "art" as a means towards this end is a good argument. Not surprisingly, I might identify Heinlein's "love" as a more encompassing ethic, but I think the intent is similar."
What if we created secular communities that were "about" having secular communities? What if we left off of our agenda having a "coherent, collective atheist world-view" and instead had an institution that fostered community and provided services without a supernatural excuse.
I myself have been looking for the consensus world view that we can all get behind as atheists. I have looked in cognitive science, philosophy of science, world religions, and sociology. We don't need One world view to handle all of our daily troubles. We need world views that can get us through. It is exactly the effort to find one value system and build off of that that has been so troubling.
That we are all human is enough commonality to start a community. The churches are freaking out that they can't hold on to the youth in their communities. This lack of "loyalty" or lack of engagement makes them look down on the people who stop coming to church at high school and don't come back until they have kids of their own. What they don't realize is that they are an institution that serves people, not representatives of God, whom people should serve. And the churches don't have anything to offer teenagers that they can’t find elsewhere.
I think that the drive to look for a central tenet of an atheist world view is the response to a bad question or a false premise. Most secularists I know don't need to believe anything in particular most of the time. Not believing anything is the regular state of most people and I don't think that needs to change. What I think most secularists need that they don't have is an institution on their side. And I see no reason that such an institution can't be built out of providing services without a coherent world view.