[AppSec]

This is really dependent on how much of the "developer" role is developing and how much is software engineering. Are the developers literally taking design documents (UML diagrams, use cases,etc) and just typing in the code or are they actually doing some analysis.

There is also the domain knowledge acquired by the developers over the course of time. I will tell you that I was part of a transition to an outside contracting company for a legacy site. The business knowledge gained and the ability to deliver solutions as a result of that enabled a much faster time to market than these guys could ever provide.