The network fibers relate to one another by function and relative need. Some fibers do more than others, but all are needed or become obsolete and cut off. Many argue that once a system exists, it should be recognized for its existence even following its demise. I see the validity of this argument but one doesn't keep a t.v. that doesn't work. This is a network provider.
Usage become the key factor.
A network should do its job correctly without having to spend excess energy on old network providers. Unless the old network provider has some alternate use that positively affects the network, it should be disregarded and life should move on. Many things in life have to be left behind in order for life to proceed at its fullest. The fibers of the network need to do their job and also respect its environment. Many environments are invaded by networks that disregard the invasion.