There are many reasons we have managers. Workers are not an abstract unit. They are human beings with human concerns and human availability. This needs to be

There are many reasons we have managers. Workers are not an abstract unit. They are human beings with human concerns and human availability. This needs to be accounted for separately from their work output. Managers allow you to create departments which are abstract units as a convenient interface over this problem. Information flows are not always efficient or desirable to have broadcast to all individual workers. Managers serve as a node in this company information graph to help manage the reality of these concerns, and to provide a mechanism where information can actually flow in the opposite direction without creating chaos. They're am imperfect solution to a worse problem.