The "shared developer code" does exist, it's about have an understanding of (1) what is required to get something complex and rife with dependencies, like ED, out the door and (2) what the term "beta" means.
And the poor blighters are using SVN if I recall correctly. I've heard it's common in game dev, cos it was always good at dealing with large binary art assets. Wonder if they've made the move to LFS yet? Probably anything that's been used for a decade on the Cobra engine is fairly well embedded into tools and workflows though.