The Gnutella network is not contiguous. There are may regions of the Gnutella network not accessible by everyone simultaneously due to the large size of the Gnutella network and effects of scaling. Network topology (virtual) is very different from the actual topology (physical). So, even though 2 computers are a mere few feet away, they are connected to different areas, which could possibly be fragmented and inefficient.

The entire network could be reached with a central server implementation, but this would make Gnutella extremely simple to terminate. In other words, a mirror image of the Napster situation.