Right, except that communication between developers is the least scalable part of running a software team. For every new member you add, there are n existing developers to communicate with, so your communication costs go up as O(n^2).

If the goal is to grow a piece of software over time (as in many startups), any architecture that relies on "better communication" is doomed to fail, simply because it limits the size of the team that can handle it (and thus growth).