Well, true. Cell tower coverage is actually very good in the kalahari desert. They build huge towers that cover cells way bigger than anything you'll find in any city. But those patch-cables they need from the tower to the backbone :). I think the OP meant something along the line "it's easier to supply a sufficiently dense network" since you probably need more antennas but in the end, it's easier to put up those antennas since you have a reliable cable connection close by.