I know it sounds excessive, but it's not really. We have a home phone and a line for our computers. There are more than enough phone numbers to go around. It's just that, historically, Federal Communications Commission rules said phone numbers had to be assigned in blocks of 10,000. So phone numbers aren't the problem.
Phone lines are.
It turns out that most older residential neighborhoods were wired with the expectation that a house wouldn't have more than one or two phone lines. Kind of like using up all the electrical outlets in a room. There's just no more juice. I guess phone lines are one of those creeping symptoms of consumption. When I was growing up, we started out with a party line, one of the last in Seattle.