Everytime someone is added, complexity is added. Agreement, understanding, shared vision, the ability to communicate effectively all become more difficult as more people are added. If less is so obviously more, why do we continually add people?
Economies of Scale
The industrial revolution and the 20th century demonstrated the benefits of economies of scale. It costs $3,000 to make 100 of Adam Smith's pins, however it only costs $4,000 to make 1,000 pins. The price for each pin goes from $30 to $4.
Where fixed costs are high and you have to build factories and assembly lines and have marketing departments and sales teams, economies of scale make a lot of sense. Is that the world we face?
Less is More
In a world where you can outsource manufacturing, marketing, legal and accounting functions and focus only on the real areas you know, do you need the extra departments? Do you need the headachs finding, hiring, training and aligning all those people?