Not OP, but imo the classic thought is that your managerial influence is directly correlated with the count and quality of employees under you. In this sense, silos get built not quite for specialization, but because your individual managerial incentive is to try to grow you and yours at the expense of (internal) competitors for a fixed budget; interoperation can be a direct threat to your influence and growth.

A famous study of behavior like this might be Kodak, and how internally the film "silo" crushed the digital "silo".