Not sure where you got your definition. The economic definition of a natural monopoly is where firms have increasing returns to scale. That means where firms c

Not sure where you got your definition. The economic definition of a natural monopoly is where firms have increasing returns to scale. That means where firms can produce more product per unit cost as the volume sold of that product gets large. https://cs.stanford.edu/people/eroberts/cs181/projects/1997-98/microsoft-vs-doj/economics/returns.html https://cs.stanford.edu/people/eroberts/cs181/projects/1997-... A good example is electricity -- it's super duper hard to put up electrical wires all around a country. But once the wires are up, it's not so hard to maintain them or extend them to cover more people over time. Google and Facebook are perfect examples. The software engineer salaries ain't cheap to build their product, but once built the products can be scaled quickly at relatively low cost. Furthermore, their products' value itself has increasing returns to scale; the more people on a social network or using a search engine, the more valuable to advertise on them.