Comcast and Verizion discovered they could use their monopoly position to sell both ends of the pipe.

Comcast I know went through and systematically shut down private interchanges with major content providers and also refused to upgrade public peering points. There were some peering points that we're seeing 10%+ packet loss. The result was terrible performance to any provider who didn't buy "internet access" from Comcast even when the only access that was needed was to Comcast's own customers.

A friend worked as a peering coordinator for a major content provider at the time and nobody had ever asked to be paid to deliver content to their own customers before. This created a standoff and I'm not sure how it ended but I believe the content providers caved.

Of course I'm pretty sure this is what was the spurred Google Fiber. One thing that Google seems really good at is to ensure that nobody can use their monopoly position to cut them off from the customer (Android, Chrome, Fiber).