[encoderer]

I believe you'll find that's also incorrect. The trouble there is that you can put only so much radio transmission power in a given "cell" on the network. In order to provide proper service to high density urban areas, you have to build more towers (more overlapping "cells") than in rural and suburban areas.

Now, you may end up having no higher a ratio of towers to subscribers than in the suburbs. But what you do have, is a lot higher costs to rent an easement for the tower. Renting antenna space from a building is a lot more expensive than an easement in some back yard.