What are examples of natural monopolies that don't have overwhelming economies of scale?
One answer I found are natural monopolies that form on the basis of significant network effects. While economies of scale decrease the cost per unit as you can produce more units, network effects increase the value per unit as you sell more units. These two things together seem like they cover everything, but I haven't read any sources that mention whether there are other situations than economies of scale and network effects. Btw, I'm including "economies of scope" in my mention of economies of scale, since they're so similar.