Both of my large scale projects are STILL being worked on, BBB and What Remains.
I had an RPG mod with a large scale build, which the mod and the build were not even complete. It is also still being worked on, in fact, all of my old big mods are still being worked on, extremely slow, though.
DayZ is a giant project as well, it can get done, but can take a super long time; which is why we need more scripters to get it done faster.