Clearly you haven't been following development on DF the last couple of years, which is when the last (partial) release came out. Bay 12 is working with Kitfox Games on this. While the brothers are still overseeing the core development of the game, they have extra people working on the other parts. Short of any other major health concerns for either one, I think they might see better progress in the future. I'm not really sure of any long term commitments from Kitfox on the game, though, beyond adding the GUI.
Honestly, the biggest thing that is needed is multi-threaded development, which is inevitable given the eventual scope of the simulation. That's going to be a bigger hindrance to future development than this. Maybe, just maybe, with the Kitfox release, they'll have the funding to get a couple of experts on the matter on a payroll.