Internet T1 bandwidth circuits are available to virtually every home and business in the United States. This is true for at least a couple reasons:
First, T1 bandwidth circuits are delivered over the same copper wires used for analog phone service. Almost all homes and businesses in the US either have or at some time in the past have had phone service. The second reason is that internet T1 bandwidth is not distance limited. This is because T1 bandwidth data packets are reestablished on average about every 6000 feet. Here is an example:
Circuit passes through the Telephone company central office (C.O.). As the T1 circuit travels between the CO and the location of the customer, all data packets are reestablished every 6000 ft (on average). Each time these packets are reestablished, they are recreated exactly. Because this occurs at near the speed of light, a T1 circuit can travel 1 or 500 hundred miles with almost no degradation, and virtually perfect quality.
The reason that DSL, Cable, and Ethernet over copper are not available at all locations is that these circuits are not reestablished, and therefore will degrade with distance. Because telecom providers do not want to provide inferior service, all three of these circuits are distance limited.
The availability of T1 also helps to explain how T1 prices are determined and why T1 is more expensive per megabit per second (mbps) than DSL, Cable and Ethernet. T1 facilities and reestablishment systems cost money. This also helps to explain why distance from CO is a major factor in determining T1 circuit price.