Because the IS tradition is one of formalisation and standardisation vs. providing flexibility to changing needs. The main organisational challenge is to understand the nature of the work that is happening in various groups, and therefore what style of IT support is needed. Too often we automate what we think is routine, but our inflexible systems cannot adapt as the 'routine' changes. The hierarchy served us well in stable times. We still need the hierarchy for some aspects of management, but not for information flows.
Todays networks are but stepping stones to neural nets.
IT enables adaptive structures. Our research has shown that too often the organisational aspects of new systems are ignored - job design, team composition, skill requirements all change. Sociologists and psychologists can tell us a lot about people. We need to move from systems engineer designed systems to user centred design approach. This is not designing systems for the user, nor letting the user design their own, but designing systems together in co-operation.