"Natural monopoly" is an economics term.
http://en.wikipedia.org/wiki/Coercive_monopoly
[Edited]
Municipalities also have natural incentives to provide sweet-heart franchise agreements -- it's generally too expensive to do otherwise once the infrastructure is in place, often partially subsidized.
We may just be disagreeing to disagree at this point. I'll let you have the last word here.
This is a one-sided description and a false dichotomy. A non-regulated natural monopoly can be just as suppressive as a government enforced-coercive monopoly. A regulated natural monopoly does not also require the creation of a government-enforced coercive monopoly.
The inefficient private solution stayed the adoption of a publicly administered one.