I think the fundamental difference, and the difference that allows large sites to get large, and keeps small (ish) sites small, is the locus of control. People who are used to centralized control much prefer it, even if they make no contribution to the work required to maintain it, and/or constantly complain about it. It's scary to them that someone else might do something they don't like, and they have no recourse to "correct" it, so they do their utmost to keep a centralized model and then do whatever it takes to influence it in their favor.
I think your designer and programmer are on the right track.
