It seems a major reason is a lack of broadband access (cost aside). While the US is very urban, most forget about the truly wide expanses of rural areas where cable does not go. Since I have moved out of "the city" into a rural area, albeit a small town, I have become more aware of this. I know some people who literally have mile long driveways and the homeowner is responsible for getting a line to the road to connect to the cable company and most do not want to incur the expense.
In the end, are people (in the story's demographics) really missing something by not using the internet.