If you take a networked enterprise approach, you are trying to optimize (in this case, maximize) the performance of a single business in a network. The unit of analysis is the single firm.
However, maximizing a single firm' s performance may affect/harm the performance of other firm(s) that are directly or indirectly connected to the firm at hand. Once the performance of the firm at hand is maximized, the performance of another firm gets the attention.
Furthermore, while optimizing this firm, the initial firm may be affected and its performance may be diminished, making the initial effort obsolete. Therefore, the life-cycle of the network is expected to be short, as the firms that once extracted maximum benefit quit the network to find other such networks to extract maximum benefit. This causes a form of a gold rush.
On the other hand, a business network approaches the network as a whole system. Here, the unit of analysis is the whole network, rather than just one participant.
The goal in business network approach is maximizing the performance of the whole system. The whole system generates a strong body against competition. While maximizing the performance of the whole system, some, if not most, of the firms cannot reach their ideal individual maximum performance, initially. However, this system that is build on trust, is expected to have a long-term life-cycle and generate long-term sustainable competitive advantage. Long-term competitive advantage will turn out to be beneficial for each participant of the system by increasing their individual performances even beyond the initial maximum point, since the synergy of the system hurt the competitiveness of outsiders.
