Yep same with electricity. A lot cheaper to hook up a huge apartment building with a ton of residents, then digging trenches between a bunch of homes. Or putting power lines up, then maintaining them.
There is also economies of scale going on. Where you can have maintenance crews and server technicians with a constant workflow, and little travel time. And specialized equipment in addition.
If it wasn't for our major cities being liberal meccas, stopping growth and doing crazed socialist engineering, I think many more people would move towards the major centers, as the cost of living would be so much cheaper.
The Chinese with their super dense cities are throwing in broadband like crazy right now.
Of course, funded by the government no less. My local telephone company is my local internet provider and they've been providing ADSL to the cities they serve for years now. Broadband for what it's worth hasn't given me any incentive to move into town. The phone company and electric company know me personally, and if I have a gripe with either one, they're right on top of it the moment I speak up. I can't say that about the internet provider. The tech support is a couple of incompetant rubes. I've actually solved more customer problems than they have. It's how I make a living.