The article didn't address the question of why AT&T has phone records going back so many years. I doubt that five year old data about a customer would be useful for marketing, considering that they have the most recent data. Nor is old data useful for billing once the time period for contesting a phone bill has elapsed. Network capacity planning could be done with anonymized or aggregated data. So it would seem that the only reason why they hang on to all this data is because the government asks them to, or because they can make money selling it to the government (or both).

Now, think about what adverse effects such old data could have on justice. For example, let's say a friend of mine from school, who I spent a lot of time talking to on the phone a decade ago, decided this year to become a drug dealer. The government could start investigating me based on this stale data, despite not having any reasonable suspicion that I was involved in any crime.

I think that what we really need is a privacy-oriented phone company built on the model of DuckDuckGo, which doesn't keep any data about customers beyond what's necessary for billing purposes. But maybe the U.S. already has laws that would make such an ethical phone company illegal.